Looking ahead to Saturday's Wyoming caucus, Democratic Sen. Barack Obama had to cope with some pesky issues of the recent week, defending himself against an ad that ran in Texas and the fallout from a former adviser's remarks.

His presidential rival, Sen. 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.