"There's no sentiment in Kentucky, and the people up here are so out of touch," Paul told reporters on a conference call after a Senate Foreign Relations Committee hearing with Kerry and other national security officials. "These senators who are going to vote for this, they need to go home and talk to their people or look at what their people are saying because people do not want to get involved in Syria and, despite what the people want, their senators are going to vote the opposite way, I have a bad feeling."
Paul didn't rule out a Senate filibuster of a resolution authorizing the president to use military force.
"Whether there is an actual standing filibuster, I've got to check my shoes and see if I can hold my water," he said. "We'll see. I haven't made a decision on that."
Sen. Marco Rubio of Florida, a fierce foe of Syrian President Bashar Assad, expressed frustration with the Obama administration's handling of Syria and skepticism about U.S. involvement.
"When America ignores these problems, these problems don't ignore us," Rubio told senior administration officials at the Senate hearing. "Yes, this is a horrible incident where perhaps 1,000 people died, but before this incident 100,000 people had died ... and nothing happened."
The administration says it has proof that the Assad regime used deadly chemical weapons in an attack on Damascus suburbs and must respond. It places the number killed at 1,429 people, including 426 children. However, the British-based Syrian Observatory for Human Rights puts the death toll at 502.
Potential Republican presidential candidates hardly want to appear weak on national security, an issue that traditionally has been a strength for the GOP. But no one knows whether the United States would be drawn into a protracted conflict or if limited military steps would prove unsuccessful in the 2-year-old civil war.
Any Republican who supports the use of force resolution essentially will be siding with Obama, who is despised in conservative circles, and a vote in favor could anger more isolationist Republicans who are wary of getting involved in another military conflict after more than a decade of fighting in Iraq and Afghanistan.
The votes could dog Republican candidates with voters in early primary states such as Iowa, New Hampshire and South Carolina. Even the most nuanced explanation for a vote could be undermined by events on the ground.
Yet if Republicans oppose the resolution, they could be accused of giving Assad a pass after his regime used chemical weapons.
Republican strategist Steve Schmidt, who managed Sen. John McCain's 2008 presidential campaign, said a vote in favor of the resolution would be the equivalent of "a purchase of stock over the long term in Obama's decision-making on Syria."
"Any Republican may go into a vote thinking, 'I have given authority for a limited scope of action to the president,' but the reality is you're buying stock in the president's current decisions on Syria and also his future actions in any escalation that may occur," Schmidt said.
Polls show public opposition to U.S. military intervention in Syria, regardless of whether Syria's government used chemical weapons on its people, and doubts about airstrikes across party lines.
A war vote can make or break a candidate. Just ask Hillary Rodham Clinton.
In the 2008 Democratic primary, Obama used the October 2002 vote for the Iraq war as a cudgel against Clinton, who along with John Edwards voted to give President George W. Bush the broad authority to invade Iraq. Edwards said his vote was a mistake; Clinton stood by her decision — and never recovered with strong anti-war Democratic voters.
Clinton, a potential Democratic candidate in 2016, has not spoken publicly about Obama's attempt to win congressional support for a military strike against Syria. But an aide to Clinton said Tuesday that she supports the president's effort in Congress to pursue a targeted response to the Assad regime's alleged use of chemical weapons.
In 2004, the first presidential election since the Sept. 11, 2001, terror attacks, Democratic primary voters rejected the anti-war candidate, Howard Dean, and nominated John Kerry, the decorated Vietnam War veteran who had backed the Iraq war. Kerry was perceived as the stronger candidate on national security against the incumbent president, but he stumbled in explaining his Iraq war votes, saying he voted for an $87 billion war supplemental "before I voted against it." Bush prevailed in the election.
For Republicans, the debate over Syria foreshadows a fierce argument in the party over the role of U.S. foreign policy and military involvement after Iraq and Afghanistan. The divisions have been simmering for months.
Paul conducted a lengthy Senate filibuster in March to raise concerns over the president's use of aerial drones to kill suspected terrorists, rallying libertarians within the party. Some establishment Republicans opposed the filibuster and pushed back against criticism of the National Security Agency's collection of hundreds of millions of U.S. phone records, saying it was needed to keep Americans safe.
In July, New Jersey Gov. Chris Christie called the libertarian strain within the GOP a "very dangerous thought" more than a decade after the Sept. 11 attacks. Paul responded, saying Christie was worried about the "dangers of freedom" instead of being concerned about losing those freedoms.
As Obama has pushed for the U.S. to intervene in Syria, the GOP divisions have emerged.
Texas Sen. Ted Cruz has expressed skepticism about possible intervention, saying the administration has yet to make a forceful case that it would protect U.S. national security interests.
The Syria question is easier to avoid outside Washington.
Christie, asked about the Syrian conflict Tuesday, told reporters the "use of chemical weapons is something that just is intolerable for civilized society," but he said he would "let the policymaking be done by the people who are getting the bulk of the briefing on this, which is our federal representatives."