Our federal government, once limited to certain core functions, now dominates virtually every area of American life. Its authority is all but unquestioned, seemingly restricted only by expediency and the occasional budget constraint.

Congress passes massive pieces of legislation with little serious deliberation, bills that are written in secret and generally unread before the vote. The national legislature is increasingly a supervisory body overseeing a vast array of administrative policymakers and rulemaking agencies. Although the Constitution vests legislative powers in Congress, the majority of “laws” are promulgated in the guise of “regulations” by bureaucrats who are mostly unaccountable and invisible to the public.

Americans are wrapped in an intricate web of government policies and procedures. States, localities, and private institutions are submerged by national programs. The states, which increasingly administer policies emanating from Washington, act like supplicants seeking relief from the federal government. Growing streams of money flow from Washington to every congressional district and municipality, as well as to businesses, organizations, and individuals that are subject to escalating federal regulations.

This bureaucracy has become so overwhelming that it’s not clear how modern presidents can fulfill their constitutional obligation to “take care that the laws be faithfully executed.” President Obama, like his recent predecessors, has appointed a swarm of policy “czars” — über-bureaucrats operating outside the cabinet structure and perhaps the Constitution — to promote political objectives in an administration supposedly under executive control.

Is this the outcome of the greatest experiment in self-government mankind ever has attempted?

We can trace the concept of the modern state back to the theories of Thomas Hobbes, who wanted to replace the old order with an all-powerful “Leviathan” that would impose a new order, and Jean-Jacques Rousseau, who, to achieve absolute equality, favored an absolute state that would rule over the people through a vaguely defined concept called the “general will.” It was Alexis de Tocqueville who first pointed out the potential for a new form of despotism in such a centralized, egalitarian state: It might not tyrannize, but it would enervate and extinguish liberty by reducing self-governing people “to being nothing more than a herd of timid and industrious animals of which the government is the shepherd.”

The Americanized version of the modern state was born in the early 20th century. American “progressives,” under the spell of German thinkers, decided that advances in science and history had opened the possibility of a new, more efficient form of democratic government, which they called the “administrative state.” Thus began the most revolutionary change of the last hundred years: the massive shift of power from institutions of constitutional government to a labyrinthine network of unelected, unaccountable experts who would rule in the name of the people.

The great challenge of democracy, as the Founders understood it, was to restrict and structure the government to secure the rights articulated in the Declaration of Independence — preventing tyranny while preserving liberty. The solution was to create a strong, energetic government of limited authority. Its powers were enumerated in a written constitution, separated into functions and responsibilities and further divided between national and state governments in a system of federalism. The result was a framework of limited government and a vast sphere of freedom, leaving ample room for republican self-government.

Progressives viewed the Constitution as a dusty 18th-century plan unsuited for the modern day. Its basic mechanisms were obsolete and inefficient; it was a reactionary document, designed to stifle change. They believed that just as science and reason had brought technological changes and new methods of study to the physical world, they would also bring great improvements to politics and society. For this to be possible, however, government could not be restricted to securing a few natural rights or exercising certain limited powers. Instead, government must become dynamic, constantly changing and growing to pursue the ceaseless objective of progress.

The progressive movement — under a Republican president, Theodore Roosevelt, and then a Democratic one, Woodrow Wilson — set forth a platform for modern liberalism to refound America according to ideas that were alien to the original Founders. “Some citizens of this country have never got beyond the Declaration of Independence,” Wilson wrote in 1912. “All that progressives ask or desire is permission — in an era when ‘development,’ ‘evolution,’ is the scientific word — to interpret the Constitution according to the Darwinian principle; all they ask is recognition of the fact that a nation is a living thing and not a machine.”

While the Founders went to great lengths to moderate democracy and limit government, the progressives believed that barriers to change had to be removed or circumvented, and government expanded. To encourage democratic change while directing and controlling it, the progressives posited a sharp distinction between politics and what they called “administration.” Politics would remain the realm of expressing opinions, but the real decisions and details of governing would be handled by administrators, separate and immune from the influence of politics.

This permanent class of bureaucrats would address the particulars of accomplishing the broad objectives of reform, making decisions, most of them unseen and beyond public scrutiny, on the basis of scientific facts and statistical data rather than political opinions. The ruling class would reside in the recesses of a host of alphabet agencies such as the FTC (the Federal Trade Commission, created in 1914) and the SEC (the Securities and Exchange Commission, created in 1934). As “objective” and “neutral” experts, the theory went, these administrators would act above petty partisanship and faction.

The progressives emphasized not a separation of powers, which divided and checked the government, but rather a combination of powers, which would concentrate its authority and direct its actions. While seeming to advocate more democracy, the progressives of a century ago, like their descendants today, actually wanted the opposite: more centralized government control.

So it is that today, many policy decisions that were previously the constitutional responsibility of elected legislators are delegated to faceless bureaucrats whose “rules” have the full force and effect of laws passed by Congress. In writing legislation, Congress uses broad language that essentially hands legislative power over to agencies, along with the authority to execute rules and adjudicate violations.

The objective of progressive thinking, which remains a major force in modern-day liberalism, was to transform America from a decentralized, self-governing society into a centralized, progressive society focused on national ideals and the achievement of “social justice.” Sociological conditions would be changed through government regulation of society and the economy; socioeconomic problems would be solved by redistributing wealth and benefits.

Liberty no longer would be a condition based on human nature and the exercise of God-given natural rights, but a changing concept whose evolution was guided by government. And since the progressives could not get rid of the “old” Constitution — this was seen as neither desirable nor possible, given its elevated status and historic significance in American political life — they invented the idea of a “living” Constitution that would be flexible and pliable, capable of “growth” and adaptation in changing times.

In this view, government must be ever more actively involved in day-to-day American life. Given the goal of boundless social progress, government by definition must itself be boundless. “It is denied that any limit can be set to governmental activity,” prominent scholar (and later FDR adviser) Charles Merriam wrote, summarizing the views of his fellow progressive theorists. “The modern idea as to what is the purpose of the state has radically changed since the days of the ‘Fathers,’” he continued, because

the exigencies of modern industrial and urban life have forced the state to intervene at so many points where an immediate individual interest is difficult to show, that the old doctrine has been given up for the theory that the state acts for the general welfare. It is not admitted that there are no limits to the action of the state, but on the other hand it is fully conceded that there are no ‘natural rights’ which bar the way. The question is now one of expediency rather than of principle.

This intellectual construct began to attain political expression with targeted legislation, such as the Pure Food and Drug Act under TR and the Clayton Anti-Trust Act under President Wilson. These efforts were augmented by constitutional amendments that allowed the collection of a federal income tax to fund the national government and required the direct election of senators (thus undermining the federal character of the national legislature).

The trend continued under the New Deal. “The day of the great promoter or the financial Titan, to whom we granted everything if only he would build, or develop, is over,” Franklin D. Roosevelt pronounced in 1932. “The day of enlightened administration has come.” Although most of FDR’s programs were temporary and experimental, they represented an expansion of government unprecedented in American society — as did the Supreme Court’s late-1930s endorsement of the new “living” Constitution.

It was FDR who called for a “Second Bill of Rights” that would “assure us equality in the pursuit of happiness.” Roosevelt held that the primary task of modern government is to alleviate citizens’ want by guaranteeing their economic security. The implications of this redefinition are incalculable, since the list of economic “rights” is unlimited. It requires more and more government programs and regulation of the economy — hence the welfare state — to achieve higher and higher levels of happiness and well-being.

The administrative state took off in the mid-1960s with Lyndon Johnson’s Great Society. By creating a truly national bureaucracy of open-ended social programs in housing, education, the environment, and urban renewal (most of which, such as the “War on Poverty,” failed to achieve their goals), the Great Society and its progeny effected the greatest expansion of the administrative state in American history.

The Great Society also took the progressive argument one step farther, by asserting that the purpose of government no longer was “to secure these rights,” as the Declaration of Independence says, but “to fulfill these rights.” That was the title of Johnson’s 1965 commencement address at Howard University, in which he laid out the shift from securing equality of opportunity to guaranteeing equality of outcome.

“It is not enough just to open the gates of opportunity. All our citizens must have the ability to walk through those gates,” Johnson proclaimed. “We seek not just freedom but opportunity. We seek not just legal equity but human ability, not just equality as a right and a theory but equality as a fact and equality as a result.”

And now progressive reformism is back. We’re witnessing huge increases in government spending, regulations, and programs. And as the national government becomes more centralized and bureaucratic, it will also become less democratic, and more despotic, than ever.

The tangled legislation supposedly intended to “reform” health care is a perfect example. It would regulate a significant segment of society that has been in progressives’ crosshairs for over a hundred years. Nationalized health care was first proposed in 1904, modeled on German social insurance. It was in the Progressive party’s platform of 1912. It came back under FDR and Truman, then Johnson, then Clinton, and now Obama. And the goal all along has had little to do with the quality of health care. The objective is rather to remove about a sixth of the economy from private control and bring it under the thumb of the state, whose “experts” will choose and ration its goods and services.

President Obama and the Democratic leadership prescribe a government-run health plan, burdensome mandates on employers, and massive new regulatory authority over health-care markets. Their requirement for individuals to buy insurance is unprecedented and unconstitutional: If the Commerce Clause can be used to regulate inactivity, then the government is truly without limit. They would transfer most decision-making to a collection of federal agencies, bureaus, and commissions such as the ominous-sounding “Health Choices Administration.” And their legislation is packed with enough pork projects and corrupt deals to make even the hardest Tammany Hall operative blush.

It would be easier, of course, just to skip the legislative process, and when it comes to climate change that’s exactly what the progressives are doing. In declaring carbon dioxide to be a dangerous pollutant, the Environmental Protection Agency essentially granted itself authority to regulate every aspect of American life — without any accountability to those pesky voters.

The Left has long maintained that the administrative state is inevitable, permanent, and ever-expanding — the final form of “democratic” governance. The rise of progressive liberalism, they say, has finally gotten us over our love affair with the Founding and its archaic canons of natural rights and limited constitutionalism. The New Deal and the fruits of centralized authority brought most Democrats around to this view, and over time, many Republicans came to accept the progressive argument as well. Seeing responsible stewardship of the modern state and incremental reforms around its edges as the only viable option, these Republicans tried to make government more efficient, more frugal, and more compassionate — but never questioned its direction.

As a result, politics came to be seen as the ebb and flow between periods of “progress” and “change,” on one hand, and brief interregnums to defend and consolidate the status quo, on the other. Other than the aberration of Ronald Reagan and a few unruly conservatives, there seemed to be no real challenge to the liberal project itself, so all the Democrats thought they had to do was wait for the bursting forth of the next great era of reformism. Was it to be launched by Jimmy Carter? Bill Clinton? At long last came the watershed election of Barack Obama.

But a funny thing happened on the way to the next revolution.

The Left’s over-reading of the 2008 election gave rise to a vastly overreaching agenda that is deeply unpopular. Large numbers of citizens, many never before engaged in politics, are protesting in the streets and challenging their elected officials in town-hall meetings and on talk-radio shows. Forty percent of Americans now self-identify as conservatives — double the amount of liberals — largely because independents are beginning to take sides. Almost 60 percent believe the nation is on the wrong track.

Voters are deeply impassioned about a new cluster of issues — spending, debt, the role of government, the loss of liberty — that heretofore lacked a focal point to concentrate the public’s anger. The Washington Post reports that “by 58 percent to 38 percent, Americans prefer smaller government and fewer services to larger government with more services. In the last year and a half, the margin between those favoring smaller over larger government has moved from five points to 20 points.” Is it possible that Americans are waking up to the modern state’s long train of abuses and usurpations?

There is something about a nation founded on principles, something unique in its politics that often gets shoved to the background but never disappears. Most of the time, American politics is about local issues and the small handful of policy questions that top the national agenda. But once in a while, it is instead about voters’ stepping back and taking a longer view as they evaluate the present in the light of our founding principles. That is why all the great turning-point elections in U.S. history ultimately came down to a debate about the meaning and trajectory of America.

In our era of big government and the administrative state, the conventional wisdom has been that serious political realignment — bringing politics and government back into harmony with the principles of the Declaration of Independence and the Constitution — is no longer possible. Yet we are seeing early indications that we may be entering a period of just such realignment. Perhaps the progressive transformation is incomplete, and the form of the modern state not yet settled — at least not by the American people.

This creates a historic opening for conservatives.

Growing opposition to runaway spending and debt, and to a looming government takeover of health care, doesn’t necessarily mean that voters want to scrap Social Security or close down the Department of Education. But it may mean that they are ready to reembrace clear, enforceable limits on the state. The opportunity and the challenge for those who seek to conserve America’s liberating principles is to turn the healthy public sentiment of the moment, which stands against a partisan agenda to revive an activist state, into a settled and enduring political opinion about the nature and purpose of constitutional government.

To do that, conservatives must make a compelling argument that shifts the narrative of American politics and defines a new direction for the country. We must present a clear choice: stay the course of progressive liberalism, which moves away from popular consent, the rule of law, and constitutional government, and toward a failed, undemocratic, and illiberal form of statism; or correct course in an effort to restore the conditions of liberty and renew the bedrock principles and constitutional wisdom that are the roots of America’s continuing greatness.

The American people are poised to make the right decision. The strength and clarity of the Founders’ argument, if given contemporary expression and brought to a decision, might well establish a governing conservative consensus and undermine the very foundation of the unlimited administrative state. It would be a monumental step on the long path back to republican self-government.

Mr. Spalding is director of the B. Kenneth Simon Center for American Studies at the Heritage Foundation and the author of We Still Hold These Truths: Rediscovering Our Principles, Reclaiming Our Future (ISI Books).