"It's about a takedown"

In moving cautiously to date, Mr. Obama may have underestimated the public's appetite for military action—especially after the beheading of two American journalists.

The poll found that 61% saw it in the nation's interest to attack ISIS. Last year, after Mr. Obama accused the Syrian government of using chemical weapons, only 21% said it was in the U.S. interest to take military action.

The president has "a country and an electorate, regardless of party, who seems to be ready to take the next step," said Fred Yang, a Democratic pollster who conducted the survey with GOP pollster Bill McInturff. That could give Mr. Obama may have a chance to reassert himself as a leader, pollsters said.

"The president seems to be controlled by events and not leading events," said Mr. McInturff. But with the public so ready to take military action against ISIS, he said, "it might allow him to perhaps use September and October to be a more strongly perceived figure than he's been."

In recent months, domestic issues have been overshadowed by crises across the globe—especially the rapid advance of Islamic State in Iraq. Mr. Obama has launched airstrikes to protect U.S. interests but has been criticized for not acting more quickly and decisively—a critique fueled last week when he said, "We have no strategy yet."

Moreover, Mr. Obama has presided over a significant decline in confidence in U.S. security: The poll found that 47% believe the country is less safe than it was before the Sept. 11, 2001 terrorist attacks—up sharply from 28% just one year ago.

The survey was taken Sept. 3-7, just after the beheading by ISIS of a second U.S. journalist. While those surveyed weren't asked directly about that event, the poll found that 94% had heard news of the two murders, a higher level of public attention than given to any of 22 news events the Journal/NBC News survey has tested since 2009.

The news, in some cases, turned doves into hawks. "Come on! They are rounding up people and just killing them," said Sara Appleton, 31, a Democrat in Austin who opposed the Iraq war and voted twice for Mr. Obama. "I think we should have intervened earlier."

Strobe Talbott, a deputy secretary of State during the Clinton administration and now president of the Brookings Institution think tank, said he left the dinner with the sense that the president is convinced the U.S. and its allies need a comprehensive approach to destroy the extremist group.

"This is not a matter of containment," Mr. Talbott said. "This is not about keeping ISIS from expanding, it is about a takedown."