Steve Kornacki writes: When you’re running near the top of the polls, it’s inevitable that your opponents will gang up on you. But there’s something different about the nature of the attacks Ron Paul is now facing – and, potentially, about their implications.

In the past few days, three of Paul’s rivals – Newt Gingrich, Mitt Romney and Michele Bachmann – have publicly declared that the Texas congressman will not under any circumstances win the GOP nomination. Bachmann called him “dangerous,” while Gingrich said he wasn’t even sure he’d vote for Paul over Barack Obama. Another candidate, Rick Santorum, said there’s no difference between Paul and Obama on foreign policy and that he’d need “a lot of antacid” to stomach voting for Paul. And Jon Huntsman launched a scathing anti-Paul ad in New Hampshire with a simple title: “Unelectable.”

This is not a run of the mill pile-on. Paul’s foes aren’t simply telling Republicans that he’s not the best choice to be their nominee; they’re telling Republicans that he’s unfit to call himself one of them – that he’s an imposter who isn’t due even the most basic courtesy (“Oh sure, if he ends up being the nominee I’ll be with him…”) that major candidates for the nomination are typically afforded.

It’s an attitude that’s also being encouraged by some of the GOP’s most powerful opinion-shaping forces. Rush Limbaugh has been disdainful of Paul throughout the campaign, with his guest host this week – Mark Steyn – keeping up the campaign. Fox News, whose primetime hosts have alternated between ignoring and savaging Paul, has been treating him like a pariah since the last campaign, when Paul was denied a seat at a critical pre-New Hampshire debate. And the New Hampshire Union Leader, which boasts one of the country’s most influential conservative editorial pages, branded Paul “truly dangerous” on Thursday.

The roots of this anti-Paul alarmism go deeper than the racist newsletters that were sent out under Paul’s name in the early 1990s and that have attracted new attention in the past week. Sure, the newsletters (and Paul’s shifting explanations for them over the years) would help make him an unelectable GOP nominee, but rest assured the same intraparty voices would be railing against him with the same adamance even if they’d never emerged.

The reason has to do with Paul’s non-interventionist foreign policy and his unapologetic mockery of the “clash of civilizations” ethos that has defined the post-Cold War GOP. Today’s Republican Party is dominated by Christian conservatives (44 percent of participants in the 2008 primaries identified themselves as evangelicals) and neoconservatives, who are united in their commitment to an unwavering alliance between the United States and Israel, confrontation with Iran, and a significant American presence in the Middle East. Paul’s warnings about “blowback” directly threaten this consensus.