His presidential rival, Senator Hillary Rodham Clinton, won the Ohio and Texas primaries Tuesday after questioning Obama's fitness to handle crises. On Wyoming's friendlier landscape, where he is expected to win Saturday, Obama seemed determined to ease voters' minds - and to take a few jabs at Clinton.
Speaking in a crowded gym in Casper on Friday, Obama alluded to Clinton's Texas ad, which suggested that only she has the experience and mettle to handle a national crisis at 3 a.m.
"That is designed to feed into your fears," Obama said.
Alternating between humor and disdain to make his points, he said: "What do people think I'm going to do? I'm going to answer the phone."
As the crowd laughed and applauded, he continued, "I will find out what's going on, and I won't be browbeaten into launching a war that wasn't necessary."
Friday's town-hall event was Obama's first major public appearance since the Tuesday setbacks, and he appeared feisty, even though his own campaign put him on the defensive to some degree.
Without prompting from the audience, he alluded to a former adviser's reported remarks suggesting that Obama, as president, might remove U.S. troops from Iraq more gradually than he has promised.
Clinton "used this to try to imply that I wasn't serious about bringing this war to an end," Obama said. "If it had been up to me, we would have never been in this war. It was because of George Bush, with an assist from Hillary Clinton and John McCain, that we got into this war."
As the crowd cheered, Obama vowed to end the war in 2009. He said Clinton "doesn't have standing to question my position on this issue" because she voted to authorize the war in 2002, as did McCain, the Republican presidential candidate.
Later, at a rally in Laramie before 8,000 people at the University of Wyoming, Obama said Clinton is so "steeped in Washington" that she cannot understand a fresher approach to politics that relies on bipartisanship and hope.
Clinton "basically believes the system is what it is," he said, and the only way to win is "to beat the other side into submission."
Obama also called Clinton "a fine public servant," drawing scattered applause.
Earlier Friday, Obama visited Johnny J's Diner in Casper, where his exchanges suggested Saturday's caucus may prove a little tougher for him than some expect.
Chris Crossen, a self-employed financial adviser, questioned the senator intently about the high price of health insurance. Crossen, 49, later told reporters that Obama described his plan to subsidize insurance for many Americans, with the caution that it could take at least two years to implement.
Crossen, a registered independent, said he wanted more details.
"I'm undecided," he said of his voting intentions.
At a nearby table, Jeanette Clark, a social worker at a privately run substance-abuse center, received a handshake and an autograph from Obama.
But in an interview, she said she will vote for Clinton. "She's trying to make a difference," Clark said. "I think it would be wonderful to have a woman as president."
To be sure, many patrons at the crowded diner applauded Obama and wished him luck. But when he left, with a cheeseburger and vanilla shake in hand, he hit another bump.
Noting the sunshine, he called out to reporters, "It's really nice in Wisconsin." Immediately catching his gaffe, Obama added, "and Wyoming!"
