PHILADELPHIA — Clashing over Iraq, Sen. John Kerry said Friday that President Bush's policies made the war against terror harder to win and "let Osama bin Laden slip away." Bush chastised his Democratic rival for questioning the motives of Iraq's interim prime minister.

"The invasion of Iraq was a profound diversion from the battle against our greatest enemy, al-Qaida," said Kerry, who argued that the commander in chief's mistakes have raised the ante for the United States in combatting terrorism.

Taking issue with Kerry's criticism a day earlier of the upbeat assessment from Iraq's Ayad Allawi, Bush told a campaign rally in Wisconsin: "You can't lead this country if your ally in Iraq feels like you question his credibility. The message ought to be to the Iraqi people: 'We support you.' The message ought to be loud and clear."

The fingerpointing capped a week of acrimony and negativism from both campaigns as Kerry, lagging in polls, tries to make an issue of Iraq and the president's credibility. On Thursday, the Democratic candidate had accused Bush and Allawi of painting a falsely optimistic portrait of life in Iraq amid continuing violence, kidnappings and beheadings. Kerry said the Iraqi leader had contradicted his earlier assessments. Coordinating their attack, Bush and Vice President Dick Cheney jumped to Allawi's defense. While the president said the prime minister is "risking his life for a free Iraq," Cheney told an audience in Louisiana that he was appalled by Kerry's criticism.

"John Kerry is trying to tear him down and to trash all the good that has been accomplished" in Iraq, Cheney said.

Bush ordered the invasion of Iraq in the spring of 2003 after telling U.S. voters and wary allies that Saddam Hussein had weapons of mass destruction, ties to terrorists and a history of defying the international community. Saddam was toppled within weeks, but more than 1,000 Americans have been killed and more than 7,000 injured in fighting with insurgents.

"Every week, too many American families grieve for loved ones killed in Iraq by terrorist forces that weren't even there before the invasion," Kerry said in a speech at Temple University.

Bush, who calls Iraq the front line in the war on terror, has said he would have made the same decision had he known no weapons of mass destruction would be found. His re-election strategy is to cast himself as a steady leader while questioning Kerry's decisiveness.

"It's very important for us not to send mixed signals to the world, not embolden these people," Bush said in Wisconsin.

Kerry argued that the president has hurt the war on terror by making bad decisions, starting with diverting attention from capturing bin Laden in Afghanistan to invade Iraq.

"Yet, in the face of all these judgments, all these misjudgments, all the miscalculations and all the mistakes, the president still says he wouldn't do anything different," Kerry said.

Kerry paused throughout his speech to cough and take sips of water as he nurses a cold, but otherwise his speech was a carefully scripted event to showcase the Democrat as the stronger enemy of terrorism six days before the first presidential debate.

His staff reminded audience members sitting in front of the podium that they would be on television, so they should pay close attention, and asked camera operators to make sure the "Fighting the war on terrorism" sign on the front of Kerry's podium was in their shots.

"As president, I will fight a tougher, smarter, more effective war on terror," Kerry said. "I will never take my eye off the ball."

Kerry offered a seven-part plan for fighting terrorism worldwide. He said the United States must secure chemical and nuclear weapons left throughout the former Soviet Union, stop nuclear weapon development in Iran and North Korea, shut down terrorist financing systems in Saudi Arabia, become independent of Mideast Oil, broker peace between Israel and Palestine and fight the poverty and disease that creates failed states.

White House press secretary Scott McClellan said Kerry "was copying the very proposals the president is pursuing on the war on terrorism."

The Bush-Cheney campaign argues that Kerry's lengthy, nuanced answers on Iraq show an inability to speak clearly and consistently. At the same time, Bush has taken to twisting Kerry's words to his own advantage. When Kerry said this week that "we have traded a dictator for a chaos that has left America less secure," Bush accused him of preferring a dictatorship in Iraq.

On Friday, Kerry said the fight was against al-Qaida and its leader bin Laden, who killed more than 3,000 people in the Sept. 11, 2001 attacks.

"George Bush made Saddam Hussein the priority," Kerry said. "I would have made Osama bin Laden the priority." He said Bush should have kept U.S. forces focused on the hunt for bin Laden. Instead, Kerry said, "the president outsourced the job to Afghan warlords who let Osama bin Laden slip away."