DES MOINES, Iowa (AP) – The assassination of Benazir Bhutto in Pakistan jolted the race for the White House on Thursday, sending candidates in both parties scrambling for political advantage while condemning the attack.

Republican Sen. John McCain of Arizona and Democratic Sen. Hillary Rodham Clinton of New York, who have made experience a cornerstone of their campaigns, said the murder was proof of a need for a president who is ready to take command.

“I know from my lifetime of experience you have to be prepared for whatever might happen, and that’s particularly true today,” Clinton said in an Associated Press interview while campaigning in Iowa.

She declined to be drawn into a discussion about the impact on a leading rival, Barack Obama, the first-term senator from Illinois who has stressed a need for change in Washington.

McCain was not so reticent about comparing his experience with that of other GOP contenders.

“My theme has been throughout this campaign that I’m the one with the experience, the knowledge and the judgment. So perhaps it may serve to enhance those credentials to make people understand that I’ve been to Pakistan, I know Musharraf, I can pick up the phone and call him. I knew Benazir Bhutto.”

Asked later by reporters about his rivals, he said former Arkansas Gov. Mike Huckabee doesn’t have “the same experience and background on national security issues that I do.”

He said former New York Mayor Rudy Giuliani had done a great job with a “post-crisis situation” after terrorists brought down the World Trade Center towers on Sept. 11, 2001. McCain added, “I’m not saying he is without credentials. I’m saying I am the one with the most credentials and the most experience and the most judgment.”

Giuliani issued a statement that said the assassination was further evidence that the United States needs to increase its efforts against terrorism – and he began running an a new TV ad focusing on the Sept. 11 attacks.

McCain made no mention of another leading Republican rival, Mitt Romney. But the former Massachusetts governor was eager to join the debate.

“If the answer for leading the country is someone that has a lot of foreign policy experience, we can just go down to the State Department and pick up any one of the tens of thousands of people who spent all their life in foreign policy,” he said while campaigning in New Hampshire.

Instead, he said, what is needed is a chief executive with leadership and the ability to assemble “a great team of people to be able to guide and direct them to understand what decision has to be made.”

The assassination of Pakistan’s former prime minister occurred one week before the Iowa caucuses, the first test of the 2008 race for the White House, and provided a reminder of the importance of national security in an era of terrorism.

In Iowa, officials disclosed that internal polling by the top three Democratic campaigns showed Clinton, Obama and former North Carolina Sen. John Edwards in a virtual dead heat. Edwards had slight momentum going into Christmas, said these officials, who spoke on condition of anonymity while discussing confidential information.

Among Republicans, private as well as public polls in Iowa show Huckabee with the lead over Romney, who had been the front-runner in the state for months. In New Hampshire, site of a primary five days after Iowa votes, Romney polls narrowly ahead of McCain, who has made gains in recent weeks as Giuliani and former Tennessee Sen. Fred Thompson have faded.

Alone among the White House contenders, New Mexico Gov. Bill Richardson called on President Bush to pressure Pakistani President Pervez Musharraf to step aside in favor of a coalition government.

“Until this happens, we should suspend military aid to the Pakistani government,” he said in a statement. “Free and fair elections must also be held as soon as possible,” added Richardson, who served as ambassador to the United Nations for a portion of the Clinton administration.

Obama said he had asked the administration for intelligence briefings on a dicey situation.

In a criticism of current policy, he said the war in Iraq had diverted troops and other resources needed to track down al-Qaida terrorists who move between Afghanistan and Pakistan. “I’ve been saying for some time that we’ve got a very big problem there,” he said.

Edwards declined to endorse Richardson’s idea on Musharraf, saying “I don’t think now is the time to talk about things like that.” He later talked with the Pakistani president and said he urged him to “continue on the path to democratization, to allow international investigators to come in to determine what happened.”

Said Huckabee: “The terrible violence surrounding Pakistan’s upcoming election stands in stark contrast to the peaceful transition of power that we embrace in our country through our Constitution. On this sad day, we are reminded that while our democracy has flaws, it stands as a shining beacon of hope for nations and people around the world who seek peace and opportunity through self-government.”

Sen. Joseph Biden, D-Del., chairman of the Senate Foreign Relations Committee, told reporters in Iowa that he had twice this past fall urged Musharraf “to provide better security for Ms. Bhutto and other political leaders. … The failure to protect Ms. Bhutto raises a lot of hard questions for the government and security services that must be answered.”

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AP Writers Ron Fournier, Mike Glover, Glen Johnson, Nedra Pickler and Liz Sidoti contributed to this story.

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