WASHINGTON >> President Barack Obama wasn’t just seeking Americans’ support for military action in Syria. He also was seeking their trust.

Whether he earned it will not only color his response to the use of chemical weapons in Syria’s civil war but also his legacy as a world leader and the success of his broader second-term priorities.

With the majority of Americans against the use of force in Syria, Obama asked them today to have confidence in his judgment as commander in chief if he launches a strike despite their opposition. And he asked them to have faith that a president elected to end wars was still trying to find another way out, perhaps a diplomatic deal at the United Nations to secure Syria’s chemical weapons.

"I know that after the terrible toll of Iraq and Afghanistan, the idea of any military action, no matter how limited, is not going to be popular," Obama said in a prime-time address from the White House, adding that he has a "deeply held preference for peaceful solutions."

No matter the outcome of the Syria standoff, keeping the public’s faith is a daunting task for Obama at a time when he’s already fending off lame-duck status. With trust intact, Obama has space to maneuver on Syria and other issues. But should he lose the public’s confidence, Obama would find it more difficult to wield influence on the world stage, much less persuade Congress to pass immigration overhaul, rally support for budget issues or build backing for critical elements of his signature health care law.

Politicians of all stripes would have little incentive to follow a weak president if the public — the people who vote for lawmakers — don’t trust him.

"The president does need the American public and the broader international community to trust his judgment on this issue, which he did not choose, in order to allow them to trust him on the issues he really does choose," said Jeffrey Engel, the director of the Center for Presidential History at Southern Methodist University.

Today’s address wasn’t the speech Obama had originally planned to give.

But rapidly moving diplomacy forced him to recast the address from one aimed at building support for a congressional use-of-force resolution to one explaining why he is he spending so much time on a matter that so many Americans oppose.

"I know Americans want all of us in Washington — especially me — to concentrate on the task of building our nation here at home, putting people back to work, educating our kids, growing our middle class," he said. "It’s no wonder then that you’re asking hard questions."

More than 60 percent of Americans want Congress to vote against authorizing a military strike against Syria, according to a new Associated Press poll. And the opposition cuts across party lines, with 53 percent of Democrats, 59 percent of independents and 73 percent of Republicans saying Congress should vote against the plan to strike Syria.

Point by point, Obama tried to address their concerns during his 15-minute address. To those who question whether it’s worth taking limited action, he argued that a targeted U.S. strike "will send a message to (Syrian President Bashar) Assad that no other nation can deliver." To those who fear Assad will retaliate, he downplayed the Syrian regime’s ability to threaten U.S. interests. And to those who fear a limited strike in Syria will ultimately pull the U.S. into a lengthy conflict, he said he had no interest in starting another war.

"I will not put American boots on the ground in Syria," he said. "I will not pursue an open-ended action like Iraq or Afghanistan."

Again and again, Obama’s message was clear: Trust me.

More than four years into Obama’s presidency, most Americans say they do — but he’s lost ground on that measure since he’s been in office.

According to a Galllup/USA Today poll out this week, 55 percent of Americans said they saw Obama as honest and trustworthy, down from a high of 63 percent in March 2008 when he was a candidate for the White House.

The president and his advisers are mindful of the damage a further slip in those numbers could have on the remaining years of his presidency.

Obama’s predecessor George W. Bush never recovered in his second term from a rapid loss of trust as the death toll in Iraq mounted and much of the intelligence used to bolster the case for war was discredited. The government’s botched response to Hurricane Katrina also was a drag on Bush’s credibility because it cemented the impression for many Americans of a president who was out of touch and lacked compassion.

Rep. Peter Welch, a Democrat from Vermont, said Obama’s efforts to distance the strike he is seeking from the Iraq war could carry weight with the president’s skeptical supporters.

"The Democrats have a lot of appreciation for the fact that we have a president who’s a war-ender, not a war-starter," Welch said. "When he says it’s limited, personally, I think Democrats believe him, because of his history. It’s not a fear that it’s George Bush and regime change."

But underscoring the uphill fight Obama faces, even Welch says he’s undecided about how he would vote on military action.