President Obama returned home from the Group of 20 summit Friday night to a country largely opposed to US military action in Syria.

In St. Petersburg, Russia, he had failed to win any support of note. On Capitol Hill, congressional whip counts of lawmaker inclinations on resolutions backing the President are way in the negative column.

Across the US, public opinion is clearly against attacking the regime of Bashar al-Assad for its use of chemical weapons against civilians. If he opened the windows at the White House Saturday, Mr. Obama would have heard demonstrators loudly protesting any US military attack on Syria. Protesters demonstrated in New York, Boston, and other cities as well.

Undeterred, the President and top administration officials are fanning out across the world, looking to find any sign of support for responding to Obama’s “red line” on chemical weapons in Syria with military might.

United Nations Ambassador Samantha Power argued the administration’s case for military action before the generally liberal Center for American Progress in Washington Friday – the kind of audience that now finds itself allied with the conservative tea party movement on Syria.

On Saturday, Secretary of State John Kerry flew to Lithuania, where he met with European foreign ministers, who agreed with the US that the Aug. 21 alleged chemical attack said to have killed more than 1,400 people appears to have been the work of the Syrian regime.

Sec. Kerry welcomed the "strong statement about the need for accountability." Still, the EU did not specify what an appropriate response would be, and in a joint statement the foreign ministers said any potential military attack against Syria should wait for a U.N. inspectors' report expected later this month.

From Vilnius, Kerry headed for Paris to meet French leaders and Arab League foreign ministers.

In his regular radio address Saturday, Obama previewed the arguments he’ll likely make Tuesday when he addresses the American people on the eve of a full Senate vote Wednesday on the resolution authorizing use of force.

"We cannot turn a blind eye to images like the ones we've seen out of Syria,” he said. “Failing to respond to this outrageous attack would increase the risk that chemical weapons could be used again; that they would fall into the hands of terrorists who might use them against us, and it would send a horrible signal to other nations that there would be no consequences for their use of these weapons. All of which would pose a serious threat to our national security.”

“That's why we can't ignore chemical weapons attacks like this one – even if they happen halfway around the world,” said Obama, who’s dispatched his chief of staff Denis McDonough to make the same points on five TV news shows Sunday.

Fox News reports that National Security Adviser Susan Rice will be giving a speech Monday at the New America Foundation, a Washington think tank.
 
 Will it be enough to turn public opinion and – perhaps more to the point – the inclination of lawmakers Obama has put in the position of having to vote on authorizing the commander in chief to go to war?

“The measure might pass the Senate, but its prospects in the House are grim,” reports The Hill newspaper. “Most House Republicans who have taken a stance are vowing to vote no or are leaning no.”
 
 Suggesting an uphill fight for President Barack Obama, House members staking out positions are either opposed to or leaning against his plan for a US military strike against Syria by more than a 6-1 margin, a survey by The Associated Press shows.

A whip count by the Washington Post has a similar result: 225 House members against military action or leaning that way compared to just 25 who’ve said they’d support the resolution.

As the AP points out, for Obama to succeed, he'll have to win about 90 percent of the undecided House members – or change the minds of those who are leaning against him.

Rep. Michael Grimm, (R) of New York, has already changed his mind, but not in Obama's favor.

"My initial reaction, as a Marine combat veteran, was to stand by the commander in chief and support immediate, targeted strikes," Rep. Grimm told the AP. But since then, he said, he has heard from many constituents "who strongly oppose unilateral action at a time when we have so many needs here at home." He now believes the benefits of a US strike won't outweigh "the extreme cost of war."

Polls show that’s essentially how most Americans feel.

Several months ago, they were more inclined to back military force in response to the hypothetical use of chemical weapons by the Assad regime in Syria.

The latest Pew Research Center poll has a plurality (48-29 percent) opposing US military action in Syria. The margin is wider – 59-36 percent opposed – in the most recent Washington Post/ABC poll.

“Americans have grown more hard-eyed – more bottom-line and realistic, less romantic about foreign endeavors, and more concerned about an America whose culture and infrastructure seem to be crumbling around them,” writes Wall Street Journal columnist Peggy Noonan.

Coincidentally, Obama’s speech Tuesday – said by some to be the most important of his presidency – comes on the 12 anniversary of the terrorist attacks of 9/11, which launched another debate about weapons of mass destruction.