The rare moment of solidarity is driven, in part, by the perception of America as a steadfast global defender of freedom and democracy. Many Americans say they see a lopsided fight pitting a great power against a weaker neighbor. They see relentless images of dead families and collapsed cities. They see Ukraine’s president pleading for help.

In polls and interviews since the attack, Americans across the political spectrum said the nation has a duty to respond to President Vladimir V. Putin’s brazen invasion — even if that means feeling, at least in the short term, the pinch of high gas prices and inflation.

“I understand we want to stay out of it, but what’s happening is worse than anyone could imagine. We can do without gas when there are children there being killed,” said Danna Bone, a 65-year-old retiree in McMinnville, Ore., and a Republican. “It’s horrific what’s happening there, and we need to be doing our part. I would like to see them doing more. What that looks like, I really don’t know.”

Yet interviews with more than three dozen Americans from Georgia to California show that, beyond broad consensus that Ukraine deserves support, they are unsettled and even divided on essential questions: How far should America go to defend Ukraine without thrusting the nation into another Cold War? Does the war demand U.S. military involvement?