It’s strange to see Tea Party favorites like Mike Lee and Rand Paul agreeing with outspoken liberals like Charlie Rangel and Alan Grayson.

Sen. Rand Paul, R-Ky., speaks to reporters Tuesday after a Senate committee hearing, voicing skepticism that President Barack Obama would decline to intervene in Syria should Congress vote against a military strike.

But the ongoing debate over congressional authorization for military intervention in Syria has produced an unusual and vocal coalition of Republican non-interventionists, liberal doves, war-weary rank-and-file lawmakers and mission skeptics who contend that any involvement in another country’s civil war is a no-win proposition.

Many members remain undecided, even as the White House lays out its case this week. But it’s clear that the president’s decision to seek congressional approval for a strike has brought typical foes onto the same side of this heated debate.

Here’s a rundown of the different voices of the opposition.

The Republican non-interventionists

Likely GOP presidential contender Sen. Rand Paul of Kentucky has frequently warred with members of his own party over national security and foreign policy issues, carving out a role as the face of a libertarian wing deeply skeptical of government surveillance and military operations abroad. On NBC’s "Meet the Press", Paul said it would be a “mistake” to involve U.S. assets in the Syrian conflict.

J. Scott Applewhite / AP Sen. Rand Paul talks to reporters on Capitol Hill in Washington on Tuesday.

During questioning at Tuesday’s Senate Foreign Relations Committee hearing, Paul said it was unclear whether a strike would increase the likelihood of more violence in the region.

“I think there’s reasonable argument that the world may be less stable because of [a strike] and that it may not deter any chemical weapons attack,” he said. “So what I want to ask is, how are we to know?”

Paul hinted to reporters after the hearing that he might require that any resolution authorizing the use of force pass the Senate by a filibuster-proof majority.

Sen. Mike Lee of Utah, Paul’s ideological ally, says he will also oppose military action in Syria, and disputes the idea that opposition is a direct result of war fatigue.

“The public’s disapproval of involvement in Syria does not stem from weariness over the past decade’s wars in Afghanistan and Iraq,” he said in a statement last week.

“Rather, the public recognizes what leaders in Washington now do not -- that after two and a half years of fighting there is still no compelling national security impetus for American military involvement in a civil war in the Middle East."

Rep. Justin Amash of Michigan, who won headlines after leading an unexpectedly close battle to gut the National Security Agency’s phone surveillance program, will hold 11 town halls this week to hear from constituents about the Syrian conflict. He’s been an outspoken opponent of intervention, retweeting veterans who oppose action in Syria to his 40,000 social media followers.

He used Twitter on Monday to slam establishment Republicans for espousing Iraq-era foreign policy strategy. “GWB-era foreign policy is nearly extinct among GOP grassroots,” he tweeted. “Some Rs in DC either didn't get the memo or haven't been home in a while.”

The outspoken liberal doves

Some members of the left who rarely disagree with the president -- and almost never miss a chance to clash with the White House’s most outspoken Republican foes -- have been a tough sell on intervention in the Middle East.

Rep. Charlie Rangel of New York, typically a loyal Democrat, derided Obama’s statement that chemical weapons use is a “red line” as “embarrassing” during an interview Monday with MSNBC.

Mark Wilson / Getty Images Rep. Alan Grayson is seen during a Oct. 1, 2009 hearing in Washington, D.C.

“I love Obama, and you’ll never find a truer Democrat than me,” Rangel said. “But this whole idea of any president of the United States drawing lines saying that if any country does something that he considers wrong that the nation is going to war, it’s unheard of, drawing a red line. So, of course, it’s embarrassing. I wish it didn’t happen.”

On Tuesday, Rangel reiterated that sentiment and said domestic issues should take precedence over a distant war.

"I don't see any reason that I can explain to my constituents that their boys and their husbands and their brothers and their sisters should be going off to fight this monster for a civil war and have that as a priority to homelessness, joblessness and all the other serious problems that we face," he said. "I can't sell that."

Democratic Rep. Alan Grayson of Florida, the liberal firebrand behind the website DontAttackSyria.com, is collecting signatures on a petition to prevent military action, arguing that “we are not the world’s policeman, nor its judge and jury.”

“It seems that nobody wants US intervention in Syria except the military-industrial complex,” he wrote in his petition.

The war-weary rank-and-file

More than a decade of war in the Middle East has left some members on both sides of the aisle simply tired of military engagement abroad, even if they think the use of chemical weapons is unacceptable.

Rep. Brian Higgins, a Democrat from western New York, raised the specters of Iraq and Afghanistan in opposing Syrian intervention.

Mark Wilson / Getty Images Rep. Rick Nolan participates in a news conference on Capitol Hill on Sunday.

"After 6,668 American troop deaths and tens of thousands of American wounded, after spending $2 trillion in Iraq and Afghanistan representing $40,000 in debt for every American family, now is the time to nation-build in America and invest in the growth of the American economy,” he said in a statement Tuesday. “It is not the time for Americans to be subjected to the potential of yet another unwinnable overseas war.”

Democrat Rick Nolan of Minnesota is seldom on the same side of a debate as onetime presidential hopeful Rep. Michele Bachmann, but both oppose intervention.

"We are war-weary,” Nolan said in a Minnesota Public Radio interview. “These wars of choice and this so-called nation-building abroad is bankrupting this country. It’s causing nothing but trouble for us throughout the world and it’s time that this Congress step up.”

The strategy skeptics

Obama and his cabinet have vowed to make the case for strikes in Syria, outlining available intelligence in painstaking detail in a series of briefings and hearings on the Hill.

But some members are skeptical of the overall case for intervention, fearing unintended consequences that could result in a protracted conflict far more complex than the series of proposed surgical strikes favored by Obama.

Jessica Hill / AP Rep. Chris Murphy is seen at debate in Hartford, Conn., on Oct. 18, 2012.

Sen. Chris Murphy, a Connecticut Democrat who serves on the Senate Foreign Relations Committee, remains leery of the administration’s strategy, although he said he will listen to the White House plead its case this week.

“The question is, is military action actually going to make the situation better on the ground for the Syrian people and how do you make sure this doesn't escalate into something much more damaging and much more bloody within the region?” Murphy said on NBC’s “Meet the Press.”

California Republican Rep. Duncan Hunter, a former Marine officer who served in Iraq and Afghanistan, said the president has squandered his best opportunity to undermine Syrian President Bashar Assad’s weapons.

“We’ve warned them we’re going to strike -- it’s the stupidest thing in the world if we are going to strike weapons caches or systems, the last thing you want to do is warn them,” he said, according to The Washington Times.

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