Independence, Mo. ? Dogged by persistent rumors questioning his belief in country, Sen. Barack Obama journeyed to Middle America on Monday to lay out his vision of patriotism, conceding that he has learned in this presidential campaign that “the question of who is – or is not – a patriot all too often poisons our political debate.”

“Throughout my life, I have always taken my deep and abiding love for this country as a given, ” Obama said in the 29-minute address to about 1,150 people crowded into a gymnasium at the Truman Memorial Building, named for former President Harry S. Truman. “It was how I was raised. It was what propelled me into public service. It is why I am running for president. And yet at times over the last 16 months, my patriotism has been challenged – at times as a result of my own carelessness, more often as a result of the desire by some to score political points and raise fears about who I am and what I stand for.”

Obama’s speech came on the same day that his rival for the White House, Sen. John McCain, pushed back hard against criticism of his own record as a Navy flier and a prisoner of war. On Sunday, retired Army Gen. Wesley K. Clark questioned McCain’s qualifications for the White House. “He hasn’t held executive responsibility,” Clark said on CBS’ “Face the Nation.” “I don’t think getting in a fighter plane and getting shot down is a qualification to become president.”

Obama rebuked that line of attack Monday, acknowledging McCain by name in saluting veterans “who have endured physical torment in service to our country.”

“No further proof of such sacrifice is necessary,” he said. “And let me also add that no one should ever devalue that service, especially for the sake of a political campaign, and that goes for supporters on both sides.” In a statement, a spokesman for the senator from Illinois said that Obama “rejects yesterday’s statement by General Clark.”

Polls have shown that a small but statistically significant slice of the electorate continues to question Obama’s patriotism, especially in white, working-class regions.

The mere act of giving the speech just four months before Election Day was extraordinary for the Democratic Party’s presumptive nominee. Obama has built his candidacy on the promise of change in a year in which a vast majority of Americans think the nation is on the wrong track. But he has repeatedly been forced to address false rumors that he will not recite the Pledge of Allegiance, place his hand over his heart during the national anthem or wear an American flag pin on his lapel. He wore a flag pin for Monday’s speech.

Obama tried to take the offensive on Monday, saying that he “will not stand idly by” while his patriotism is questioned.

Obama’s speech put the issue in a broad historical perspective, speaking of charges that Thomas Jefferson had sold the nation out to the French and that John Adams “was in cahoots with the British.” He also questioned policies enacted in the name of patriotism, including Adams’s Alien and Sedition Acts, Abraham Lincoln’s suspension of habeas corpus and Franklin D. Roosevelt’s internment of Japanese Americans.

“The use of patriotism as a political sword or a political shield is as old as the republic,” Obama said. “Still, what is striking about today’s patriotism debate is the degree to which it remains rooted in the culture wars of the 1960s – in arguments that go back 40 years or more. In the early years of the civil rights movement and opposition to the Vietnam War, defenders of the status quo often accused anybody who questioned the wisdom of government policies of being unpatriotic.”

But he was quick to say the ’60s-era protesters did their part to bring on those charges “by burning flags, by blaming America for all that was wrong with the world, and perhaps most tragically, by failing to honor those veterans coming home from Vietnam, something that remains a national shame to this day.”

And he tried to put the issue of patriotism into his own, unusual biography, which took him as a child from Hawaii to Indonesia, from a home headed by a single mother to one led by grandparents.

“For a young man of mixed race, without even a father’s steadying hand, it is this essential American idea – that we are not constrained by the accident of birth but can make of our lives what we will – that has defined my life, just as it has defined the life of so many other Americans,” he said. “That is why for me, patriotism is always more than just loyalty to a place on a map or a certain kind of people. Instead, it’s also loyalty to America’s ideals, ideals for which anyone can sacrifice, or defend, or give their last full measure of devotion.”