I love that Barack Obama chose Springfield, Mo., to start firing back at John McCain. I used to live there.

Speaking to supporters today in a heavily Republican area  (House Minority Whip Roy Blunt's home district), Obama took aim at McCain's negative tone and challenged him to a "duel" on tax policy.

As Reuters reports:

Obama, launching a four-day tour of swing states to promote his economic policies, mocked the arguments he said McCain, a Republican Arizona senator, and his supporters will make.

"'He's not patriotic enough. He's got a funny name. He doesn't look like all the presidents on the dollar bills,'" Obama said.

"That's their argument. 'We don't have much to offer, but he's risky,'" he said. "We are in a time right now where it is too risky not to change. It is risky to keep doing what we are doing."

Obama's comments came McCain launched a new ad likening the Illinois senator to celebrities like Britney Spears and Paris Hilton, implying he was a lightweight who could not deliver on his talk.

"I don't pay attention to John McCain's ads, although I do notice he doesn't seem to have anything very positive to say about himself," Obama told reporters after visiting a diner in Lebanon, Missouri.

"He seems to only be talking about me," Obama said. "You need to ask John McCain what he's for, not just what he's against."

Obama seemed to finally be taking the fight back to McCain, just as several major news organizations began highlighting McCain's increasingly negative tone.

As that great Missouri president Harry Truman might have said, "Give 'em hell, Barack."