The president is up against a growing caucus of “no” on both sides of the aisle. | AP Photos Libertarians, liberals unite on Syria

Barack Obama won over Nancy Pelosi and John Boehner on using force in Syria, but the fight’s not over.

Obama’s still up against a growing caucus of “no” in Congress on either side of the political spectrum — led by libertarian conservatives, who are redefining the Republican Party’s vision of foreign policy, and joined by liberal doves.


The same informal alliance has pressured Obama before. In July, conservatives and liberals in the House joined forces on a bill to curb the National Security Agency’s sweeping surveillance programs, failing by just a handful of votes.

( PHOTOS: Syria: Where politicians stand)

It’s an open question whether the same alliance can build an even bigger coalition this time, stare down a president and pull off a true win — especially when congressional leaders are already behind Obama.

But at the very least, they aren’t going to be quiet as the debate unfolds.

Sen. Rand Paul (R-Ky.), a tea party favorite who is leading the charge in the Senate, is already threatening one of his signature moves — a filibuster.

( Also on POLITICO: Paul plan binds Hill approval, Syria)

“I can’t imagine we won’t require 60 votes on this,” Paul said in a conference call with reporters. “Whether there is an actual standing filibuster, I’ve got to check my shoes.”

Meanwhile, Sen. Marco Rubio (R-Fla.), who had earlier supported intervention to take out the Bashar Assad regime, now appears poised to oppose a resolution authorizing force against Syria — a move that could inspire other conservatives to vote no, too.

In the House, the early stages of an anti-Syria campaign have begun. A number of conservative lawmakers have taken to email to game out possible action for when the House returns to Capitol Hill next week.

( Also on POLITICO: Rubio shifts direction on Syria)

One option they say they hope to replicate is the recent floor fight in late July over an amendment to curb the NSA’s power to collect phone data from Americans. The provision, which narrowly failed 205-217, did not break along the typical ideological lines in the House, with conservatives and liberals banding together to buck party leadership and the White House.

“I think you are going to have a lot of votes, if you look at the 205 we had against some very specific limits on the [NSA], which were actually not as broad as they were made out to be. That’s a pretty powerful coalition,” Rep. Tim Huelskamp (R-Kan.) told POLITICO. “ I think many of us will stay together.”

( PHOTOS: Scenes from Syria)

Rep. Justin Amash (R-Mich.), who spearheaded the NSA vote, held half a dozen public events on Syria on Tuesday and planned another handful Wednesday.

He tweeted that after hearing from about 400 constituents Tuesday, 95 percent were against action in Syria.

“I don’t think the American people are ready to go to war based on circumstantial evidence,” Amash told a Michigan outlet, mlive.com. “The case for going to war is not that strong, in any event. … The issue has to remain whether this is in the interests of the United States to get involved. If we go there, are we going to cause more bloodshed or less? That’s not clear to me.”

Rep. Thomas Massie (R-Ky.) said he also believes the opposition could prevail, though it will be difficult.

“I think if the vote were today it would fail,” Massie said. “And I’m hopeful, but I’m well aware that once members return to D.C. they are going to be under a lot of pressure, particularly if our leadership and the committee chairmen are for this engagement, and after a week in D.C. some of the lean nos could become leans yes. I’m concerned about that.”

Kentucky’s Paul also pointed to the NSA vote as a good example of Republicans and Democrats coming together on an issue.

“I’ve been talking to other senators who I think are like-minded. I’m also talking to conservative constitutionalists in the House. I think our best chance for ultimate victory is in the House,” Paul said. “I think the only problem here is because it is so high-profile that some Democrats are going to vote party politics over their conscience. It will be close.”

On the left, liberals are starting to organize, too.

A Congressional Black Caucus official wrote in an email to member offices to “limit any public comment on the subject of Syria” until after they are fully briefed. Other liberals like House Democratic Reps. Gerry Connolly (Va.) and Chris Van Hollen (Md.) are penning alternative resolution because they believe Obama wants “far too broad authority” for action in Syria.

While this liberal-and-libertarian coalition has been out in front of issues that would later become more mainstream ideas, including opposing the Iraq War to supporting gay marriage and medical marijuana, it’s unclear whether it can rally to kill the resolution in the House.

At the very least, it is yet another example of rank-and-file Republican lawmakers being unafraid to buck party leaders on high-profile votes. Boehner put the onus on Obama to make the sell and corral enough House votes.

There are even some fissures among GOP leadership — House Majority Whip Kevin McCarthy (R-Calif.) split with Boehner and Majority Leader Eric Cantor. He has not committed to supporting the Syria resolution.

The conservative Republican Study Committee has not taken a position on Syria, but is slated to meet before the House takes up the issue.

RSC Chairman Steve Scalise (R-La.) did not commit to a position in a statement.

“Any action taken by the United States regarding Syria must be carefully considered in terms of what is in the best interest of our nation and our close allies in the region, especially Israel,” Scalise said. “The authorization to use limited military force should depend on clear military objectives and policy goals, and I look forward to the debate after these details have been laid out by the administration.”

The developing Republican infighting is also an indicator of how much pressure Minority Leader Nancy Pelosi will be under to keep her troops, especially those who feel burned on the previous Iraq War vote, in line.

Pelosi first supported Obama publicly last week after a conference with the National Security Council. “It is clear that the American people are weary of war. However, Assad gassing his own people is an issue of our national security, regional stability and global security,” Pelosi said in a statement at the time.

Kansas Republican Huelskamp said his entire state delegation, except for Rep. Mike Pompeo, who has called for a more robust Syria plan, would oppose any involvement.

“I didn’t find one single Kansan, whether liberal, conservative or in the middle, that were supportive of risking American lives or dollars in this sectarian quagmire,” he said.

Rep. Chris Gibson (R-N.Y.), a retired Army colonel, said he believes a “military strike will make matters worse and it could potentially Americanize the Syrian civil war.”

He added, “At this time of sequester, the parties need to be working together on a pro-growth, fiscally responsible replacement for the sequester.”

Even veteran lawmakers like Rep. Sam Johnson (R-Texas) — a decorated combat veteran — said they remain skeptical.

“I strongly believe the Obama administration has failed to articulate a clear mission and path to victory. Can they answer the simple question — What are our clear objectives?” Johnson said in a statement. “The administration has to answer some tough and gripping questions before I will vote to put our military men and women in harm’s way.”

Jonathan Allen contributed to this report.