One of the sharpest exchanges Friday night in the presidential debate between Senators John McCain and Barack Obama came on the issue of taxes. When Mr. McCain charged that his opponent had “voted in the United States Senate to increase taxes on people who make as low as $42,000 a year,” Mr. Obama replied: “That’s not true, John. That’s not true.”

“That’s just a fact,” Mr. McCain responded. “Again, you can look it up.”

So what does the record say when you look it up? Is one candidate right and the other wrong, or are both exaggerating?

In the past, Mr. McCain has characterized Mr. Obama’s position on taxes in ways that proved to be demonstrably inaccurate. His remarks on Friday night, which he amplified on the campaign trail on Monday, seemed to be an effort to shift him away from that shaky ground. However, they too contain assertions that are misleading or overstated.

Mr. McCain’s campaign has made it clear that he intends to portray Mr. Obama as an advocate of tax increases in the home stretch of the presidential race. Appearing Sunday on “Meet the Press” on NBC, Mr. McCain’s senior strategist, Steve Schmidt, said Mr. Obama’s voting record on taxes was “different from what he says out on the campaign trail” and was “a recipe for disaster for the economy.”