Five years ago, no one, not even Congressman Paul, would have imagined that 21 percent of voters in a hotly contested Republican caucus would support the Texas congressman’s brand of antiwar, constitutional conservatism and libertarianism. Paul didn’t just improve on his 2008 showing last night, he’s brought his philosophy from an asterisk in the Republican Party of George W. Bush to as much as a fifth of the vote in the GOP of 2012; there’s a fair chance he’ll win 20 percent again, or close to it, in New Hampshire.

Paul hasn’t come as far as quickly as the religious right did in the 1970s and ’80s or the Goldwater movement did in the 1960s. But those are the closest parallels to what he’s achieving, and the change he’s bringing about is arguably more profound. (The religious right, after all, could adapt and build upon pre-existing conservative infrastructure in the ’70s. The Paul movement is almost starting from scratch.)

More significant than the overall percentage Paul claimed last night, however, is the 48 percent he won of the under-30 vote. This augurs more than just a change in the factional balance within the GOP. It’s suggestive of a generational realignment in American politics. The fact that many of these young people do not consider themselves Republican is very much the point: Paul’s detractors cite that as a reason to discount them, but what it really means is that the existing ideological configuration of U.S. politics doesn’t fit the rising generation. They’re not Republicans, but they’re voting in a Republican primary: at one time, that same description applied to Southerners, social conservatives, and Reagan Democrats, groups that were not part of the traditional GOP coalition and whose participation completely remade the party.

There’s more at stake here than the future of the Republican Party, though. The style as well as substance of Ron Paul’s movement is radically different from the 1990s right, and the substance itself is different not only in terms of what Paul’s supporters want but what their priorities are. This is true even within the subset of people who identify as libertarians: in the generation past, for example, libertarians were just as engaged in the culture war as liberals and conservatives were — it certainly wasn’t hard to find libertarians motivated as much by abortion-rights as by concerns about monetary policy or war. The forces that effectively defined the political universe between the 1960s and 1990s, for libertarians, conservatives, and liberals alike, were civil rights, the sexual revolution, and the disintegration of the Great Society. A generation before that, unemployment, fascism, and communism had been among the spectrum-shaping issues. Now something else is coming into view. The old pillars of politics don’t go away — communism still mattered a great deal in 1970s, and culture-war issues still matter today — but weight shifts to other structures over time. Paul has inaugurated such an architectonic shift.