By Thomas Ferraro
WASHINGTON (Reuters) - What will Mitch do?
That's a big question in the U.S. Capitol, where so far Senate Republican leader Mitch McConnell is the only one of the "Big Four" congressional leaders who has not backed President Barack Obama's call for military strikes against Syria.
What McConnell will do is an even bigger question back home in Kentucky, where he is in a tough re-election campaign and under fire on this and other issues from the political right and left.
McConnell, a pivotal player in Senate battles, said this week he needs more information about Obama's drive to punish Syria for suspected use of chemical weapons before making a decision.
After congressional leaders were briefed by Obama this week, McConnell said, "Congress and our constituents would all benefit from knowing more about what it is he thinks needs to be done - and can be accomplished - in Syria and the region."
With most of his 99 Senate colleagues undeclared and polls showing the majority of the public opposed, McConnell's decision will help determine the fate of a Senate resolution to authorize limited military strikes.
Obama's Democrats hold the Senate, 54-46, but 60 votes would be needed to clear anticipated procedural roadblocks.
Republicans backing military strikes include John McCain of Arizona and Lindsey Graham of South Carolina, two leading lawmakers on national security issues. Republicans opposed include McConnell's deputy, assistant Senate Republican leader John Cornyn, and Ted Cruz, a favorite of the conservative Tea Party movement and likely 2016 White House contender.
In Kentucky, Democrats and right-wing Republicans attack and mock McConnell for failing to take a public stand.
"He's continued to run scared," said a spokesman for Alison Lundergan Grimes, McConnell's top Democratic Senate challenger.
Matt Bevin, a McConnell Republican primary opponent, has produced a campaign video that portrays McConnell's position on Syria as an unsettling silence.
Senate Democratic leader Harry Reid, who supports military strikes, has received no indication from McConnell about what he will do, a Democratic aide said on condition of anonymity.
But the aide said "the fear" among Democrats is that he will follow the lead of Republican Senator Rand Paul, a popular fellow Kentuckian and Tea Party favorite who opposes the resolution and is expected to make a 2016 presidential bid.
Still, McConnell's longtime reputation as a "hawk" on military matters leaves room for doubt. "He may 'vote no, hope yes,'" the aide said, employing a Capitol Hill term for members who feel compelled politically to vote against the outcome they privately prefer.
Tea Party-backed Republicans opposed to military strikes, who have never much liked McConnell, say it also demonstrates he's not conservative enough.
On Syria, McConnell is following the wishes of constituents, who "want a considered position, not a rushed position," said spokesman Don Stewart.
McConnell and other congressional leaders received a briefing from Obama at the White House on Tuesday. Afterward, McConnell issued his statement that more information is needed.
Speaker of the House of Representatives John Boehner and House Democratic leader Nancy Pelosi were apparently satisfied, however, and declared their support. Reid had announced his backing earlier.
Senate Republican candidate Bevin released a video on Friday that compared the two candidates' positions on Syria, and included a number of clips of Bevin in recent interviews.
"We have absolutely no business being there," Bevin declared in one. "What would be the purpose?" he asked in another.
The video then goes silent and blank, except for the printed words: "Mitch McConnell's thoughts on Syria."
The previous day, a Grimes news release ripped into McConnell on a number of fronts, including, "Mum and Noncommittal On Crisis In Syria."
At the U.S. Capitol, a Republican aide defended McConnell.
"There's been a lot of knee-jerk criticism of him, but he's setting a good example. He intends to make an informed decision. That's what they all should do," the aide said.
(Editing by Fred Barbash and Doina Chiacu)