Well, that certainly didn’t take long. On July 3, news reports said Senator John McCain, worried that he might lose the election before it truly started, opened his doors to disciples of Karl Rove from the 2004 campaign and the Bush White House. Less than a month later, the results are on full display. The candidate who started out talking about high-minded, civil debate has wholeheartedly adopted Mr. Rove’s low-minded and uncivil playbook.

In recent weeks, Mr. McCain has been waving the flag of fear (Senator Barack Obama wants to “lose” in Iraq), and issuing attacks that are sophomoric (suggesting that Mr. Obama is a socialist) and false (the presumptive Democratic nominee turned his back on wounded soldiers).

Mr. McCain used to pride himself on being above this ugly brand of politics, which killed his own 2000 presidential bid. But he clearly tossed his inhibitions aside earlier this month when he put day-to-day management of his campaign in the hands of one acolyte of Mr. Rove and gave top positions to two others. The résumés of the new team’s members included stints in Mr. Bush’s White House and in his 2004 re-election campaign, one of the most negative and divisive in memory.

Almost immediately, the McCain campaign was using Mr. Rove’s well-honed tactics, starting with an attempt to widen this nation’s damaging ideological divide by painting Mr. Obama as a far-left kook. On July 18, Mr. McCain even suggested that Mr. Obama is a socialist to the left of the Senate’s only avowed socialist: Bernie Sanders of Vermont.