President Bush took his re-election campaign to Pennsylvania Tuesday, which is expected to be a crucial state in the November presidential election. Meanwhile, some military veterans are coming to the defense of Mr. Bush's Democratic opponent, Senator John Kerry.

President Bush addressed a rally at a helicopter plant in Pennsylvania where he defended the U.S.-led invasion of Iraq and vowed to continue American leadership in the war on terrorism if he is re-elected.

"I wake up daily trying to best figure out how to protect our country," the president said. "I will never relent in bringing justice to our enemies and secure the homeland whatever it takes."

Four years ago, Mr. Bush narrowly lost Pennsylvania to Al Gore. But since then, the president has made more than 30 trips to the state in hopes of shoring up support in November. Pennsylvania is one of 17 so-called battleground states that are expected to be closely contested in this year's election.

Democratic presidential candidate John Kerry was off the campaign trail Tuesday. He will address national security and military matters during a speech to the Veterans of Foreign Wars convention in Cincinnati on Wednesday, the same group President Bush spoke to earlier in the week.

Meanwhile, a group of military veterans have come to Senator Kerry's defense over his military record during the Vietnam War.

The pro-Kerry veterans group responded to a series of television advertisements by another veterans group that accused Senator Kerry of lying about his war record.

Retired General Wesley Clark, who earlier this year sought the Democratic Party's presidential nomination, joined several other Vietnam-era veterans at a Washington news conference to denounce the attacks on John Kerry's war record.

"They are even stooping to the level of trying to distort John Kerry's military service," he said. "It is wrong. It is the worst form of politics. The American people want the truth. They want the facts. They want honest dialogue on important issues of the day and that is why we are here."

Bush re-election officials have said Senator Kerry's service in Vietnam was honorable and have also said they had nothing to do with the veterans group that put on the ads critical of the Massachusetts senator.