BOISE - U.S. Sen. Jim Risch voted against President Barack Obama's proposed strike against Syria's chemical weapons infrastructure, underscoring skepticism among Idaho's representatives in Congress about the plan.

The measure passed 10-7 Wednesday in the Senate Foreign Relations Committee, moving it to the full Senate floor when Congress reconvenes Monday.

This week, Risch and Sen. Mike Crapo, along with Reps. Mike Simpson and Raul Labrador, all told The Associated Press they're dubious a strike would really enhance U.S. power abroad, bring a swifter end to Syrian President Bashar Assad's regime or enhance Middle East stability.

Obama says Assad's government is responsible for numerous gas attacks, including one Aug. 21 that the U.S. says killed 1,429 people. The Britain-based Syrian Observatory for Human Rights, which collects information from a network of anti-government activists in Syria, says it has been compiling a list of the names of the dead; its toll has reached 502.

Before voting against the measure, Risch told Secretary of State John Kerry during a hearing Tuesday that he's worried Assad could emerge a bolder, more-dangerous figure following strikes that aren't aimed at toppling his regime.

"If we go in with a limited strike, and the day after, the week after, or the month after, Assad crawls out of his rat hole and says, 'Look, I stood up to the strongest power on the face of this Earth - and I won,'" Risch said.

The Republican senator said classified intelligence he has seen has convinced him Assad's government is "unquestionably" behind chemical weapons attacks.

However, he's doubtful Obama's proposed response - not all-out war, rather surgical strikes aimed at crippling Assad's chemical weapons capacity - and its aftermath have been sufficiently calculated. He added he met months ago with some members of Syria's fragmented opposition, and so far isn't confident a moderate faction would emerge to take the reins, even should Assad be deposed.

Risch also said nothing he has heard so far adequately addresses his questions about the reaction of Syrian allies including Russia and the militant group Hezbollah, with its rockets in Lebanon pointed at Tel Aviv, following a U.S. strike.

"They are poised, on the northern border of Israel, with a lot of rockets they've brought in. What happens when they get into it with Israel? There's no answer to that," Risch told AP.

This week, Russian President Vladimir Putin warned the West against taking one-sided action in Syria but also said Russia "doesn't exclude" supporting a U.N. resolution on punitive military strikes if it's proved Damascus used poison gas on its people.

Sen. John McCain, R-Ariz., voted for the resolution, while House Speaker John Boehner of Ohio also backs intervention.

Simpson is ordinarily one of Boehner's staunchest allies, but an aide to the eight-term Idaho Republican said the speaker can't count on old allegiances in the Syrian question.

"He's strongly leaning against supporting military action," said Nikki Watts, Simpson's spokeswoman in Boise. "However, he's waiting to pass final judgment until he returns to Washington, D.C., next week, where he'll attend intelligence briefings and listen to floor debates."

Meanwhile, Labrador has praised Obama's move to allow Congress to weigh in on the matter.

Still, the second-term Republican has left little doubt where he stands: So far, Obama and Kerry haven't made the case that key U.S. security interests are at risk.

"They weren't really sure what their mission was," Labrador told the AP in an interview Wednesday. "I don't see a clear defined mission. ... We shouldn't be in there just to make a point, just to get a shot across the bow. I don't think that should ever be a reason for us to engage militarily."

Crapo acknowledged the deaths of more than 100,000 people during the Syrian civil war and the displacement of 2 million refugees, but said his support for a resolution would be contingent on Obama and Kerry convincing him U.S. involvement would actually protect America's national security interests.

"A high bar must be set when considering the engagement of armed forces personnel," the Republican said in a statement. "The president has the responsibility of explaining fully to the American people how intervening in Syria is a part of our strategic interests in the Middle East."