The politics of a strike on Syria: Learn everything you need to know about the latest Syria developments in less than 80 seconds. (The Washington Post)

A new Washington Post-ABC News poll finds Americans moving away from President Obama’s position as he tries to build public support for a military strike against the Syrian government.

Overall, more than twice as many Americans oppose attacking Syria as support such action, 64 percent to 30 percent. Opposition is up from 59 percent in a Post-ABC poll last week, with the largest shift among Republicans. Fully 71 percent of Republicans now oppose launching airstrikes, up from 55 percent last week.

While showing little change from last week, nearly seven in 10 independents remain opposed (69 percent), as do 55 percent of self-identified Democrats. As in the previous survey, there is no political or demographic group in which a majority supports military action in Syria.

Despite the flagging support for intervention, a 57 percent majority endorses Obama’s decision to seek congressional authorization for military action. If he is unable to rally lawmakers, though, three-quarters say they would oppose a strike.

A Senate committee passed a resolution last week supporting a more limited form of action; the latest Washington Post count estimates that a majority of lawmakers in the House are at least leaning against a strike. But even if the Congress does give its authorization, that would persuade only 14 percent of the public to move from opposition to support. Nearly half, 48 percent, would continue to oppose action, while 44 percent would support it.

Opposition to action in Syria on the rise

A “no” vote in Congress would move opposition to military action from 65 percent to 76 percent, with 17 percent remaining in favor.

Obama’s campaign of media interviews and a prime-time address Tuesday will test the limits of the bully pulpit to overcome a clear communications deficit. In a Pew Research Center-USA Today poll, 54 percent of respondents said Obama has not been clear enough in explaining why the United States should strike Syria; a number up six percentage points from last week after continuous public debate and news coverage.

The Pew-USA Today poll, along with two other surveys released Monday, also found wide opposition to military action. In a CNN-ORC survey, 59 percent of respondents said Congress should not pass a resolution authorizing military action, and more than six in 10 independents and Republicans oppose such a move. Similarly, 61 percent of respondents in an Associated Press-GfK poll said Congress should vote against a strike.

The Post-ABC poll was conducted Sept. 4-8 on conventional and cellular phones among a random national sample of 1,020 adults. The margin of sampling error for overall results is plus or minus 3.5 percentage points.

Peyton M. Craighill contributed to this report.

Where Congress stands on Syria

Against/lean no