In an invisible primary where it seems everyone other than Jon Huntsman and Rick Santorum is fated to have his or her brief day in the sun, two new polls from Iowa show the indefatigable Ron Paul now leading the field among likely caucus-goers, with just two weeks left before actual voting occurs. The media, much to the consternation of fanatical Paulists, is already writing him off as another flash-in-the pan, his libertarianism too extreme to gain the support of moderate conservatives and too at odds with social conservatives to win over their vital support. This is the right instinct—Paul will not win the nomination—but then how to explain his growing popularity? The truth is that, with the singular exception of his Chomskyesque views on foreign policy, Paul is not nearly as divorced from mainstream conservative thought as was the case four years ago.

As it has been for past candidates with a small but intense and highly organized following (most famously Pat Robertson in 1988), Iowa is indeed a promising environment for a Paul upset. That’s partly because it is a caucus state where the number of supporters it takes to win is limited, and partly because Paul has made important inroads with key groups like home-schoolers and college students. Moreover, the steadiness of Paul’s support has given him staying power even as other campaigns have undergone feast-and-famine swings. What’s perhaps most remarkable about the new Public Policy Polling survey that gave Paul his first Iowa lead is how similar the numbers look compared to results published back in April, which showed Romney in the twenties and Gingrich, Paul and Bachmann in the teens. Paul’s poll “surge” is actually a matter of adding seven points over the last eight months.

The reason Paul has been able to slowly build his base of support in the state is that, on most issues, his views no longer lie outside the mainstream of the party orthodoxy. It’s become one of the great clichés of 2012 that the GOP as a whole has moved significantly in Ron Paul’s direction since his last campaign in 2008, and on domestic issues, it’s largely true. Paul’s endless fulminations about profligate monetary policy and the evil Fed, as well as his draconian prescriptions for a radically smaller federal government, now all sound completely within the conservative mainstream.

This development is due, in part, to the fact that there is now a Democratic administration that all Republicans are happy to demonize. More subtly, Paul’s narrative of a long disastrous national slide into socialism, which sounded very weird to many Republicans when their party controlled the White House and Congress, has become commonplace, as have hints and (for some) outright arguments that the entire New Deal and Great Society legacies need to be dismantled.

A Democratic administration has also made it possible for Republicans to disparage, with some degree of impunity, current military engagements in Afghanistan and Libya, while concerns over the economy have generally placed foreign policy issues on the back burner. But in a conservative-movement-dominated GOP, ideological purity is more important than ever, and by any standard Ron Paul flunks every foreign policy and national defense litmus test imaginable. Paul’s views on the projection of American power abroad are sure to get a thorough airing if he does win in Iowa, sending him right back to the fringe status he occupied in 2008.