Just before the 4th of July, the Pew Research Center released a fascinating study of Americans' political beliefs, dividing them into seven categories from "steadfast conservatives" to "solid liberals." But what separates liberals and conservatives isn't always what they believe. It's why they believe.

By Pew's standards, I should be a liberal: I use public transportation, have a graduate degree, and am more interested in Shakespeare than fishing. In practice, I'm much closer to being a steadfast conservative. Yet many of the liberal beliefs strike a partial chord with me.

According to Pew, solid liberals -- 88 percent of them -- believe the "U.S. economic system unfairly favors powerful interests." Sure, sometimes it does. The elderly are a powerful interest, and younger people are taxed to pay their benefits. And runaway American cronyism helps explain why the counties around Washington, D.C., are so rich.

By and large, though, I believe the U.S. system is fair, because it rewards effort and middle-class values. If you graduate from high school, get a job, get married, and stay married, the odds are good you won't be poor. What bothers me about the liberal view is that it doesn't recognize big government isn't the cure for powerful interests, because it ends up working for the interests.

Liberals distrust the system, but they love immigration: An overwhelming 93 percent believe "immigrants today strengthen our country because of their hard work and talents." I'm proud my great-grandparents emigrated from what is today Poland. They worked hard, though no harder than millions like them. But it's not only a matter of hard work. The United States isn't just about making money. We're also a political community, founded on a Constitution, with laws and unique values. My ancestors came here legally, and deliberately decided to become Americans. Doing that also strengthens the United States, in a way liberals fail to recognize.

Liberals also love diplomacy. According to Pew, 91 percent believe that "good diplomacy is the best way to ensure peace." Unfortunately, Pew offered a binary choice between military strength and diplomacy. So, liberals grabbed their pens, and conservatives grabbed their guns. Too many Americans -- liberals and conservatives --think that way: it's either pens or guns, not both. Americans typically say we should try diplomacy first and then, if that fails, use force. In reality, good diplomacy marches arm in arm with power, though not always military power.

For example, if we're negotiating a trade treaty and you don't give me a fair deal, you won't get access to my market. That's using the threat of being kept out to make diplomacy effective. Diplomacy and strength aren't alternatives: they work together. The problem isn't that liberals like diplomacy. The problem is that liberals are right: the world is multicultural. People are different. They have different values and want different things. That's fine. But because those differences are real, talking doesn't always work. If you believe in multiculturalism, you can't believe that diplomacy is a cure-all.

And, finally, liberals are optimistic: 70 percent believe America's best days are ahead. But liberal optimism stems from the belief that the United States has the ability to change, not from faith in an enduring set of American principles.

Conservatives accept that change is a national strength: otherwise, we'd still be 13 weak colonies. But we believe change is aimless unless you have principles to guide you. And we believe they are to be found in the Constitution.

But conservatives believe that change comes best from individuals. What separates liberals and conservatives isn't belief in change. It's that conservatives don't think politicians have the right, or the ability, to remake society. It's not about change. It's about who, in a free society, should be in charge.

 - Ted R. Bromund is a senior research fellow in Anglo-American relations with the Margaret Thatcher Center for Freedom at the Heritage Foundation.