Who's the centrist in the 2008 election?

Both McCain and Obama want the mantle of a change agent and one capable of reaching across party divide. This article in the Philadelphia Inquirer from John Lott, research scientist at University of MD, contests the Obama charge that McCain is McSame, or a clone of George Bush. He writes:

Does John McCain represent a third Bush term? The Obama campaign claims the two are almost indistinguishable. It was the mantra during the Democratic convention, and it is the theme of new ads Barack Obama is running. The ads claim that McCain is “no maverick when he votes with Bush 90 percent of the time.”
This week Obama has begun a constant refrain that there is “not a dime worth of difference” between Bush’s and McCain’s views. It is a consistent theme of Democratic pundits on talk shows.
Is this the same McCain who drove Republicans nuts on campaign finance, the environment, taxes, torture, immigration and more? Where has McCain not crossed swords with his own party?
As it’s being used, the 90 percent figure, from Congressional Quarterly, is nonsensical. As Washington Post congressional reporter Jonathan Weisman explained, “The vast majority of those votes are procedural, and virtually every member of Congress votes with his or her leadership on procedural motions.”
Obama might want to be a little careful with these attacks, as the same measure has him voting with Democrats 97 percent of the time.

Anyone who has followed McCain’s career knows that he has not been an easy vote for the Republican leadership on certain issues. Dr. Lott details some of those issues. Attempts to paint McCain as a lock-step Republican fail when scrutinized.