DES MOINES, Iowa - Terrorism - and who's best equipped to deal with it - came roaring back as the top presidential-campaign issue yesterday after Pakistan's Benazir Bhutto was assassinated one week before Iowans begin the voting for a new commander in chief.

Candidates who have struggled to convince voters that worldly experience matters had fresh urgency for tough talk on terrorism.

Sen. Hillary Rodham Clinton (D., N.Y.), who has been emphasizing her depth of experience, pounded home her message with new vigor and a personal touch.

"I have known Benazir Bhutto for more than 12 years," the former first lady told a crowd of a few hundred at a fire station in Denison.

Clinton spoke of how she visited the then-prime minister in the 1990s, and how "we stayed in touch over the years, met on several occasions, always talked about her commitment to bringing democracy back to Pakistan."

On the Republican side, yesterday's events underscored the essential message of Arizona Sen. John McCain that it is a tough world and he knows how to deal with it.

At his first Iowa event, a town-hall meeting at an Elks Club here, McCain dispensed with his usual warm-up jokes, giving the standing-room-only crowd a somber, extemporaneous speech on Bhutto's assassination, its potential geopolitical impact, and what he would do as president to deal with "a very tense and unsteady time in Pakistan."

"I know the players, I know the individuals, and I know the best way to address the situation," McCain said.

Other candidates quickly picked up the beat.

In Urbandale, former Sen. Fred Thompson (R., Tenn.) discussed the assassination for about 15 minutes without notes. He asked the crowd to consider the possibilities, and how a man of his experience at least could understand them.

In New Hampshire, Republican Mitt Romney said the assination underscored the need for Western nations to support moderate Muslims and oppose violent extremism. The former Massachusetts governor rejected the suggestion that McCain or former New York Mayor Rudy Giuliani would be better equipped to deal with terrorism as president.

"If the answer for leading the country is someone who has a lot of foreign-policy experience, we can just go down to the State Department and pick up any of the tens of thousands of people who spent all their life in foreign policy," Romney said.

Giuliani, who has made his city's response to the Sept. 11 attacks the centerpiece of his campaign, was in Florida yesterday. He said in a statement that Bhutto's death "is a reminder that terrorism anywhere . . . is an enemy of freedom. We must redouble our efforts to win the terrorists' war on us."

Other Democrats reminded voters yesterday how long they had been working on these issues.

New Mexico Gov. Bill Richardson, a former U.S. ambassador to the United Nations, scheduled what aides called a "major speech" today in Des Moines about Pakistan and the antiterrorism effort.

Richardson said that President Bush should pressure Pakistani President Pervez Musharraf to quit and that if Musharraf won't, the United States should cut off military help to the government.

Not all candidates were as eager to adjust their pitches.

The reduction in violence in Iraq and elsewhere in recent months had brought domestic issues to the fore in the campaign, and candidates with virtually no international experience, notably Sen. Barack Obama (D., Ill.) and Republican former Arkansas Gov. Mike Huckabee, have moved up.

Huckabee, in a statement, called the assassination "devastating news for the people of Pakistan."

Obama stuck to his script, a message of change and hope, as he wowed a crowd of about 400 at downtown Des Moines' Scottish Rite Masonic Center.

He mentioned the assassination briefly at the start of his stump speech, saying: "We have to make sure that we are clear as Americans that we stand for democracy, and that we will be steadfast in our desire to end the types of terrorist attacks that have blighted not just Pakistan but the rest of the world."

Former Sen. John Edwards (D., N.C.) recalled meeting Bhutto and said late yesterday that he spoke to Musharraf "a few minutes ago, and I urged him to continue the democratization process."