After their big election gains, congressional Republicans must now commit to getting the federal budget under control. Unfortunately, some have advocated cutting the defense budget as part of the solution. Reducing defense spending now would be a dangerous mistake.

It’s important for conservatives to get this issue right. To that end, here are a few observations.

First, the framers of the U.S. Constitution envisioned national defense as the priority obligation of the federal government. The first power granted to the president in Article 2 is “Commander-in-Chief of the Armies and Navies of the United States, and of the Militias of the Several States.” Of the 17 powers granted to Congress in Article 1, six relate specifically to defense, and the Constitution grants Congress the full range of authorities necessary to establish the defense of the nation (as it was then understood).

The other powers granted to Congress are permissive in nature; Congress can choose to exercise them or not. But the federal government is constitutionally obligated to defend the nation. Article 4, Section 4 states that the “United States shall guarantee to every State a republican form of government and shall protect each of them against invasion.”

That means, for those who take the Constitution seriously, that national defense is a higher priority than other areas of federal activity. While other parts of the federal budget may be presumptively suspect, spending on the national defense is not.

Second, every category of international risk facing the United States is demonstrably growing. Islamist extremists remain a formidable threat. They are fighting to reconstitute their safe havens in Afghanistan and to acquire weapons of mass destruction for use against the United States. The Commission on the Prevention of Weapons of Mass Destruction Proliferation and Terrorism — a bipartisan panel with the status of the 9/11 Commission — found unanimously that terrorists would “more likely than not” develop and use a weapon of mass destruction against a Western city by 2013. The director of national intelligence publicly agreed with that dire assessment.

Nuclear technology and weaponry advances are cascading through rogue and failing states around the world. Pakistan — an unsteady partner facing an existential threat from terrorists — has a substantial and growing nuclear arsenal. The U.S. must be diligent in ensuring that those nuclear assets stay out of the hands of terrorists. Both North Korea and Iran are steadily increasing the range, payload, and accuracy of their ballistic missiles. No one seriously believes that the Iranians will voluntarily stop their nuclear program or that the West (except perhaps the Israelis) will use force to stop them.

Finally, the last few years have seen the rise of aggressive “peer competitors” who are developing the military capacity to challenge the vital national interests of the United States. China, for example, is rearming at a rate far ahead of American intelligence predictions.

According to most reports, China has the most sophisticated cyber-warfare capability in the world. The Chinese already boast an arsenal of advanced fighters and missiles able to deny the U.S. Navy access to the Taiwan Strait. They are building as many as five submarines per year and have established a modern submarine base on the island of Hainan. They have announced plans to build destroyers with the explicit purpose of developing a credible blue-water navy.

Meanwhile, American military strength ebbs. The military is approximately 40 percent smaller than it was when Desert Storm was fought in 1991, and the Pentagon’s inventory of “platforms” — primarily ships, aircraft, and tracked vehicles — is old, less and less reliable, and increasingly out of date technologically. The Navy has fewer ships than at any time since 1916. The Air Force is as small as it was before Pearl Harbor. The Army needs to replace its inventory of combat vehicles.

In short, the military faces a crisis in modernization that can no longer be ignored. Earlier this year, Congress created a blue-ribbon independent panel to review the Pentagon’s strategic plans. Chaired by former defense secretary Bill Perry and former national-security adviser Stephen Hadley, the panel included members from across the political and ideological spectrum. It concluded that the military was headed for a “train wreck” unless the basic inventories of the services were recapitalized. The panel endorsed various reform measures to achieve savings in current programs, but it also determined that, even if those savings could be achieved, “a substantial additional investment, beginning right away and sustained through the long term,” would be necessary to meet the crucial modernization needs.

Fortunately, it is well within the government’s capacity — even in these difficult budgetary times — to find the necessary funding. Congress could reverse the decline in military capability simply by capturing the unspent portion of the stimulus package and spending it judiciously on modernization over the next five years. As the panel report demonstrated, it is possible to marshal a strong bipartisan consensus for such an effort.

The problem is not budgetary. The problem is getting our government leaders to focus on the vital connections between strength, prosperity, and freedom. The best and cheapest way to protect American security is to sustain American power at a level that reduces risk, encourages global economic growth, and deters the wars that cost America so much in lives and treasure.

As Ronald Reagan was fond of saying, “Of the four wars that happened in my lifetime, none occurred because America was too strong.”

Jim Talent is a distinguished fellow at the Heritage Foundation.