The main thrust of the McCain campaign has been to cover up his history of economic malpractice. Senator McCain has largely pulled it off so far, under the guidance of Steve Schmidt, a Karl Rove protégé. A Rovian political strategy by definition means all slime, all the time. But the more crucial Rove game plan is to envelop the entire presidential race in a thick fog of truthiness.

Congress’s investigation of the Justice Department is of the utmost importance. It now seems clear that the department, under Attorney General Alberto Gonzales, operated as a partisan political actor, using its prosecutorial authority to help the party in power win elections. That was a grave abuse, which undermined American democracy.

Senator Obama’s advisors said that combative edge was essential to blunt any progress Senator McCain was making as he sought to encroach on Mr. Obama’s trademark message of change. But Mr. Obama’s remarks are curiously reminiscent — right down to that mocking tone — to words he spoke nearly a year ago when Senator Hillary Rodham Clinton suddenly tried to swipe the mantle of change and Mr. Obama demonstrated a fight that many had doubted he could muster.

Gov. Palin went from Sarah Who to conservative rock star in less than a week. In less than two months, she could be elected to serve under the oldest president ever elected to a first term. Intense, independent scrutiny by The Times and the rest of the news media of Palin’s background, character and record was inevitable and right.

In last the three months, Senator McCain’s campaign has been a transformed into an elbows-out, risk-taking, disciplined machine. The catalyst for the change is Steve Schmidt, a veteran of the winning 2002 Congressional and 2004 presidential campaigns, where he worked closely with Karl Rove, President Bush’s senior strategist.