KANSAS CITY — Republican presidential candidate John McCain makes short work of assessing the wartime perspective of his Democratic opponent.

His summation of Barack Obama’s position on the Iraq war: wrong, wrong and wrong.

“I hope he learns that he was wrong when he said the surge would fail,” Mr. McCain said here Thursday. “He was wrong when he said we should withdraw according to a timetable and not facts on the ground.”

Mr. McCain, talking on his campaign bus, the Straight Talk Express, on the way to a town-hall meeting at Kansas City’s Union Station, believes successes in Iraq vindicate his faith in the strategy of increased troop levels.

In supporting the surge, he told a handful of Missouri reporters on the bus, Mr. McCain said he encountered the skepticism of editorial writers and the opposition of Democratic politicians, including Mr. Obama. The presumptive Republican nominee said he trusted American leaders in Iraq to guide the U.S. strategy, despite its unpopularity.

“I was willing to lose a campaign rather than lose a war,” the Arizona senator said.

At Union Station, more than 800 people gave his message a warm welcome, applauding also the candidate’s calls for lower taxes, offshore drilling for oil and an end to pork-barrel spending.

Calling Missouri a “battleground state” and vowing to return often during the campaign, Mr. McCain insisted he didn’t mind trailing in the polls. “I’m the underdog,” he told the crowd. “That’s what I love.”

On the bus ride from the downtown airport, the Republican urged Congress to act immediately in authorizing President Bush’s request to open offshore areas to oil and natural gas exploration. He discounted estimates that it would take many years to get new energy resources into the marketplace.

Reducing America’s dependence on foreign oil remains a national security, environmental and economic priority, Mr. McCain said, and he praised the possibilities of wind, solar and nuclear energy development. He declined, however, to support fuel exploration in Alaska’s Arctic National Wildlife Refuge, believing it should remain protected.

“If they discovered oil in the Grand Canyon, I would not agree to drill in the Grand Canyon,” he said.

Mr. McCain lambasted Congress for what he called “a spending spree of unprecedented proportions.” At the meeting, the candidate said lawmakers often get accused of spending like drunken sailors. “As a former drunken sailor, I resent (that),” he said.

Confronted with a question about the cost of two wars, he countered that military spending is now less as a percentage of the gross national product than it was during the Cold War.

Partisanship, the senator said, stands in the way of addressing sweeping national problems, such as the solvency of the Social Security system. He urged a return to the thinking that guided Republican Ronald Reagan and Democrat Tip O’Neill to view all options and rescue Social Security in 1983.

“The problem in Washington is we’re totally gridlocked,” he said. “We’re putting our party ahead of our country.”

Jason Brown of Platte City, a wounded Iraq war veteran and a state representative, liked what Mr. McCain was selling at Union Station.

He met the senator in the spring of 2007, with dissent against the Iraq surge at its height. “All the pundits said ‘withdraw, withdraw, withdraw.’ The senator stood alone practically,” Mr. Brown said. “Sen. McCain is very clear that we have to win, and the majority of Americans agree with that.”

Others were less taken with Mr. McCain’s economic message. Bridgette Williams, president of the Greater Kansas City AFL-CIO, issued a statement comparing the senator’s proposals to those of the current administration.

“The truth is that Sen. McCain’s plan is little more than a carbon copy of the failed Bush agenda that has led to a rapidly collapsing economy,” the union chief said. “From skyrocketing gas prices to the health care crisis, McCain offers more of the same.”

Scott Garten, an instructor at Northwest Missouri State University, attended with his wife, Louise, and enjoyed Mr. McCain’s energy initiatives.

“I especially like that he favors nuclear power and he favors offshore drilling,” he said. “It can liberate us from foreign oil.”

Ken Newton can be reached

at kenn@npgco.com.