BARACK OBAMA has found something that eluded him during the primary season - contrast. And, he's basking in it. “He will not bring change,” Obama always asserts, rightly or wrongly, of rival Republican John McCain. “I will.” In McCain, the likely Democratic nominee faces an opponent who is the opposite of him - an Iraq war backer who supports free-market economics, opposes abortion rights and is a Republican. Obama delights in pointing out the differences, and does so often. To be sure, McCain returns the favor at his campaign events. But vast disagreements with McCain - on everything from economic philosophies to security proposals - seem to have given Obama license to more aggressively and enthusiastically go after his foe. It's a turnabout from his more cautious approach in the Democratic primaries when he faced Hillary Rodham Clinton, a fellow Democrat with whom he differed little. These days, Obama assails McCain's position on the issues every chance he gets. He levels his charges with a commonsense tone and lighthearted touch that couches the criticism while making his core argument: McCain and President George W. Bush are the same. “If you are satisfied with the way things are going now, then you should vote for John McCain,” Obama says before rattling off a list of current concerns, including rising gas prices, home foreclosures and job losses as the country fights two wars. Then, Obama promises “fundamental change.” He sought to stay on point with that pitch last week despite hitting a couple of bumps. A precautionary detour to Missouri because of a malfunctioning plane meant scuttling a North Carolina event. Obama briefly forgot to ask his donors to help retire Clinton's debt at a fundraiser intended, in part, to do just that. And, two allies caused a stir; the Rev. Jesse Jackson criticized Obama while comedian Bernie Mac made eyebrow-raising jokes during an introduction. Even so, a seemingly unfazed Obama tore through the week with McCain in his sights, giving the impression that he's becoming at ease with his newfound role, and, perhaps, running for president on the whole. At times, he came across witty and hip, relaxed and confident, and much more comfortable than he was during the heat of the primaries. Perhaps it's because there's now a measure of clarity in the race, with an opponent from the other camp with a completely different take on the issues. Perhaps it's because polls show Obama slightly ahead while McCain has seemed unable to lay a glove on him. Perhaps it's because the campaign days are lighter - at least for now. Regardless, Obama probably would be wise to guard against becoming too comfortable. If the primary race taught him anything, it's not to take anything for granted or coast through the next few months. That may be one reason why the Democrat seemingly has been relentless in contrasting himself with McCain. At a Georgia appearance, Obama noted McCain's long support for the Iraq war and objections to a withdrawal timetable. Conversely, Obama said: “I opposed this war from the start” and “I will bring this war to an end.” Later, in New York, Obama noted that McCain wants the landmark Supreme Court decision that legalized abortion to be overturned. Conversely, he said, “I will never back down in defending a woman's right to choose.” And, in Virginia, Obama argued that McCain's tax policies benefit big corporations and wealthy people more than the middle class. Conversely, he said, he wouldn't “favor Wall Street over Main Street.” McCain campaign spokesman Tucker Bounds dismissed the criticism, saying: “Whether he's ditching positions for his own political gain or launching partisan attacks, Barack Obama has shown that he's your typical politician.” Another tactic Obama employs is to use McCain's words against him. He reads them aloud, pauses dramatically and chuckles with the crowd before making his point. “Sen. McCain said, ‘Our dangerous dependence on foreign oil has been 30 years in the making, and was caused by the failure of politicians in Washington to think long-term about the future of the country,”' Obama said Friday in Dayton, Ohio. “I couldn't agree more,” Obama said. Then, smiling and in an incredulous tone, he added: “The only problem is that out of those 30 years, Sen. McCain was in Washington for 26 of them!” The crowd whooped and hollered. Obama also is taking full advantage of the openings McCain presents. Shortly after a McCain economic adviser dubbed the United States “a nation of whiners” in a “mental recession,” Obama took to the stage in Fairfax, Virginia, on Thursday and used Phil Gramm's comments to portray McCain as out of touch. “Let's be clear. This economic downturn is not in your head. It isn't whining to ask government to step in and give families some relief!” Obama said. This audience ate up Obama's criticism of McCain - just like his crowds do every day. – AP __