Last night, Paul Ryan took the highly suggestive step of delivering a foreign policy address and leaking it to the magazine that’s been crusading for him to run for president. There is, however, one ideological snag.

Ryan's budget is a Grover Norquist fantasy that would so starve the government of revenue that the only way to avoid deep defense cuts would be for the entire non-defense, non-entitlement portion of government to disappear entirely:

Perhaps the single most stunning piece of information that the CBO report reveals is that Ryan's plan "specifies a path for all other spending" (other than spending on Medicare, Medicaid, Social Security, and interest payments) to drop "from 12 percent [of GDP] in 2010 to 6 percent in 2022 and 3½ percent by 2050." These figures are extraordinary.  As CBO notes, "spending in this category has exceeded 8 percent of GDP in every year since World War II."
Defense spending has equaled or exceeded 3 percent of GDP every year since 1940, and the Ryan budget does not envision defense cuts in real terms (although defense could decline a bit as a share of GDP).  Assuming defense spending remained level in real terms, most of the rest of the federal government outside of health care, Social Security, and defense would cease to exist.

In reality, Ryan's budget is unworkable and something would have to give. Many Republicans, and especially the neoconservatives forming the draft-Ryan committee, loath the idea of pressuring the defense budget. Ryan’s forceful endorsement of neoconservative principles, along with his continued opposition to defense spending cuts, reassures his base. In the neoconservative world, mighty declarations of willpower always trump puny arithmetic.

The political angle of Ryan’s foreign policy speech is to pick up the attack line that President Obama denies American exceptionalism. Here’s Ryan:

There are very good people who are uncomfortable with the idea that America is an “exceptional” nation…
Today, some in this country relish the idea of America’s retreat from our role in the world. They say that it’s about time for other nations to take over; that we should turn inward; that we should reduce ourselves to membership on a long list of mediocre has-beens.
This view applies moral relativism on a global scale. Western civilization and its founding moral principles might be good for the West, but who are we to suggest that other systems are any worse? – or so the thinking goes.
Instead of heeding these calls to surrender, we must renew our commitment to the idea that America is the greatest force for human freedom the world has ever seen.

Ryan is referring to, without explicitly saying so, a widespread conservative claim. In April 2009, a reporter asked Obama if he believed in American exceptionalism. Obama began by citing objections to the concept before endorsing it:

I believe in American exceptionalism, just as I suspect that the Brits believe in British exceptionalism and the Greeks believe in Greek exceptionalism. I'm enormously proud of my country and its role and history in the world. If you think about the site of this summit and what it means, I don't think America should be embarrassed to see evidence of the sacrifices of our troops, the enormous amount of resources that were put into Europe postwar, and our leadership in crafting an Alliance that ultimately led to the unification of Europe. We should take great pride in that.
And if you think of our current situation, the United States remains the largest economy in the world. We have unmatched military capability. And I think that we have a core set of values that are enshrined in our Constitution, in our body of law, in our democratic practices, in our belief in free speech and equality, that, though imperfect, are exceptional.

An endless parade of conservatives have truncated the quote, ending it after the first sentence, to make it sound like a disavowal of American exceptionalism. In other words, it’s utterly false, and therefore a fitting theme for Ryan’s foreign policy message.