The Tea Party movement formed in early 2009 to protest an Obama administration housing and bank bailout proposal, gathered strength opposing ObamaCare and taxes, and evolved into a reliably Republican voting and advocacy force. There has always been some tension between the Tea Party and GOP leadership — especially in Speaker John Boehner's (R-Ohio) House. But it's always been the Tea Party trying to pull the GOP to the right.

Now, the Tea Party is linking arms with bearded leftist peaceniks — literally — at rallies opposing U.S. intervention in Syria, says Trip Gabriel in The New York Times. The first time Clark County (Indiana) Tea Party Patriots leader Kelly Khuri found herself protesting alongside progressive anti-war activists, she tells The Times, "it kind of freaked me out."

But Khuri's Tea Party group appears to be the rule rather than the exception on Syria. "I haven't seen grass-roots response this huge since that first opposition to TARP," says Matt Kibbe, the president of FreedomWorks, which recently urged lawmakers to oppose intervention in Syria. How did we get here?

In Congress, the libertarian faction of the GOP has been gaining ground since George W. Bush left office and former Rep. Ron Paul (R-Texas) became a prominent voice, now represented most vocally by Paul's son, Sen. Rand Paul (R-Ky.). Along with opposing taxes, regulation, and government generally, the libertarian Republicans tend to be wary about intervening abroad.

The first sign that a real alliance of "progressive anti-war Democrats and isolationist Tea Party libertarians" was actually materializing, says Greg Sargent at The Washington Post, was the narrow defeat of a proposal by conservative Rep. Justin Amash (R-Mich.) and liberal stalwart Rep. John Conyers (D-Mich.) to restrict NSA domestic phone surveillance.

We're already seeing substantial numbers of members who voted to end NSA surveillance now coming out or leaning against action in Syria.... In both cases — on Syria, and on the amendment to end NSA surveillance — this loose alliance of lawmakers is allied against the leadership of their own parties. And in both cases, they represent a genuine threat to the outcome. [Washington Post]

The conservative anti-war wing in Congress still pales in comparison to the stay-out-of Syria fervor among rank-and-file Tea Partiers. It's not all bottom-up: Tea Party–aligned commentators like Glenn Beck are just as vocally against intervening in Syria as liberals like Dennis Kucinich and Rep. Alan Grayson (D-Fla.). But in a movement that's proudly free of any central spokespeople, there's more going on than marching orders from Beck.

A big part of it is money: Wars are expensive, even if they're tiny ones waged by very costly Tomahawk missiles, and the Tea Party wing of the GOP views the Pentagon's massive budget as less sacrosanct than traditional or mainstream Republicans.

More skeptical observers "see simple obstructionism, not philosophical fundamentals, in the emerging anti-war wing of the right," says Patrik Jonsson at The Christian Science Monitor. In this view, "the anti-war push is simply part of a philosophy that sees any federal government action as illegitimate." It's an open question, though, whether this antiwar enthusiasm is even "a genuine philosophical viewpoint or simply more political obstructionism of Mr. Obama's agenda," Jonsson says.

"If this were a Republican president making the exact same case, more Republicans would be supportive," says the Cato Institute's Justin Logan.

Whatever the reason, the GOP/Tea Party "isolationist strain is proving increasingly popular," say McClatchy's David Lightman and Maria Recio. "The Senate's potential 2016 Republican presidential candidates all are pushing non-intervention and finding appreciative audiences."

It's an open question "whether the Tea Party becomes a long-term anti-war force, outlasting the Syria issue — which contains an element of bald anti-Obama sentiment," says The New York Times' Gabriel. Kibbe, the FeedomWorks president, says the Ron Paul wing of the party really is gaining ground over the neo-conservatives and hawks who have held sway since the Eisenhower administration.

"There's a recentering or realignment going on in the Republican Party," Kibbe tells The New York Times. And at least for now, the Tea Party has a new driving purpose.