The men competing to be commander in chief for the next four years marked Memorial Day in deeply personal ways yesterday, with President Bush acknowledging "great costs" of the two wars he launched and Sen. John F. Kerry (D-Mass.) paying quiet tribute to comrades lost in Vietnam.

Bush laid a wreath at the Tomb of the Unknowns at Arlington National Cemetery, bowing his head for the playing of taps. Then he stepped under the marble arch of the Memorial Amphitheater, where he spoke in front of three huge American flags.

"Through our history, America has gone to war reluctantly, because we have known the costs of war," Bush said. "And the war on terror we're fighting today has brought great costs of its own."

Kerry, decorated for heroics as a swift boat captain in Vietnam's Mekong Delta, began the day with his annual visit to the Vietnam Veterans Memorial. He later flew to Portsmouth, Va., to watch with Gov. Mark R. Warner (D) one of the nation's oldest Memorial Day parades, in the heart of Virginia's heavily military coastal communities.

Speaking later to Hampton Roads television stations, Kerry abandoned the day's solemnity and said he offers a choice between keeping Bush's tax cut for the wealthiest Americans or making health care more available, tuition more affordable and jobs more plentiful. "You can't do both," he said. "I think it's time to tell the truth. People want the truth."

Kerry has decided to campaign aggressively in Virginia, a state that traditionally votes Republican in presidential races. His campaign sees vulnerability as Bush's political standing has dropped in polls since last Memorial Day.

A year ago, fresh off his "Mission Accomplished" carrier landing, the president's approval rating was over 60 percent. Now, it is in the 40s, and the military's image has been tainted by the abuse scandal at Iraq's Abu Ghraib prison. Casualties in Iraq and Afghanistan are mounting, and polls show many Americans concerned about the troops' safety.

In Bush's remarks, he asserted that all 25 million Iraqis "live in freedom," despite the volatile security and political conditions there as the United States prepares to turn over limited authority to an interim Iraqi government June 30. Praising Americans in uniform, he said, "Because of their fierce courage, America is safer, two terror regimes are gone forever, and more than 50 million souls now live in freedom."

Bush was introduced by Defense Secretary Donald H. Rumsfeld, who received an enthusiastic reception from the crowd. The president has resisted calls for Rumsfeld's resignation for his handling of the Abu Ghraib abuses, and Bush drew applause for backing his Pentagon chief once again.

Across the Potomac River, Kerry walked to the Vietnam Veterans Memorial with the family of William Bronson of Gardner, Mass., who died in 1976 from a seizure related to a head wound suffered in 1968 during combat in Vietnam. Kerry had helped the family get Bronson's name added to the wall.

While in Portsmouth, Kerry watched as 60 units from the Army National Guard, submarine veterans, the fleet reserve, Coast Guard auxiliary and others marched past a reviewing stand. It was the 120th year for the parade.

Warner, who has been mentioned as a possible vice presidential pick for Kerry, flew on the senator's campaign plane from Washington to appear with him in Portsmouth. Warner endorsed Kerry several days before the state's primary in February, and Kerry is scheduled to hold a barbecue fundraiser in Northern Virginia with Warner on July 16.

The pair worked a rope line for a half-hour after the parade, shaking hands and signing baseball caps. Several people yelled, "Kerry-Warner."

Kerry's trip to Virginia came just days after his campaign announced it would defy conventional political wisdom and campaign in the commonwealth despite a decades-long losing streak for Democratic presidential candidates. Virginians have voted for a Democrat once in the past half-century -- for Lyndon Johnson in 1964. Jimmy Carter lost Virginia in 1976 even as he won the rest of the South over Gerald Ford.

Even so, Kerry's campaign officials believe his credentials from his Vietnam service will appeal to voters in Virginia, especially along the state's coastal communities such as Portsmouth, where military bases abound. Tomorrow, his campaign will begin a statewide television campaign, part of a $17 million effort in 19 states. The ads, which will run on cable in Northern Virginia, will be largely biographical, campaign officials said.

The campaigns will continue their battle for the high ground on national security today. Vice President Cheney is to fly to Kansas City, Mo., for a speech attacking Kerry for criticizing the Patriot Act, which gave broad eavesdropping and surveillance powers to agents investigating terrorism.

In West Palm Beach, Fla., Kerry is scheduled to deliver the second of three major speeches during an 11-day focus on national security -- this one "on the urgent need to prevent terrorists from acquiring nuclear weapons," according to his campaign.

The Democratic National Committee released an Internet ad yesterday accusing Bush of plotting to cut funding for veterans. "Credibility Is On the Ballot This November," the ad concludes. Republicans said the ad was false and in poor taste, given the day.

Shear reported from Portsmouth.

President Bush stands with Maj. Gen. Galen B. Jackman during a ceremony at Arlington National Cemetery's Tomb of the Unknowns. Sen. John F. Kerry (D-Mass.) hugs Barbara Bronson at the Vietnam Veterans Memorial. Kerry helped get the name of Bronson's son on the wall.