Anchored by Jake Tapper, The Lead airs at 4 p.m. ET on CNN.
The latest on national protests. Plus, what went wrong in Yemen rescue attempt?
Republican Sen. Marco Rubio, a member of the Senate Foreign Relations Committee, has made it clear for the last two years that inaction in Syria is a bad idea.
Because the U.S. chose to "lead from behind," and didn't help moderates overthrow a weaker President Bashar al-Assad early in the rebellion, it now has no good options for a military intervention, Rubio said in an interview with CNN's Jake Tapper.
"The ideal outcome in Syria is one in which Assad falls, and is replaced by a stable, moderate government," said Rubio. "That may no longer be possible."
Assad leaving could instead trigger chaos, said the Florida senator.
"The large number of radical Islamists who now find themselves in Syria means that if Assad were to fall – if he stays in power, that's obviously bad, because it empowers Iran, and so forth – but if he falls, it's also possible it could trigger a second civil war," said Rubio.
"We are really in a bind here, and again, directly the result of the president's mishandling of this entire situation," said Rubio.
Secretary of State John Kerry has stated he believes Syrian rebels and moderates on the ground are doing better.
"He's going to try and make that case in a closed hearing, so we'll hear him out. But I have serious reservations about whether that is true," said Rubio.
Republican senators Ted Cruz and Rand Paul, who like Rubio won their Senate seats with the support of the tea party, are decidedly against a strike.
"U.S. military force is justified only to protect the vital national security interests of the United States," Cruz told reporters Saturday.
"I haven't had one person come up to me and say they're for this war. Not one person," Paul said at Tuesday's Senate hearing.
Few tea party members support a U.S. strike on Syria.
"Military intervention is one of the tools in the toolbox of our foreign policy," said Rubio, adding that his concern is there is "no military intervention at this stage" that could lead to an outcome favorable to America's national security interests.
The strike currently proposed by the administration is meant to prevent Assad from using chemical weapons in the future.
"Assad is using these weapons because he's trying to survive. ... I don't think three days worth of missile strikes is going to dissuade him from doing whatever it takes to survive in the future," said Rubio.