CHICAGO (AP) – 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 in every way – an Iraq war backer who supports free-market economics, opposes abortion rights and is a Republican.

New tactics

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 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.”

Troubles this week

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.

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.