The Iraq war remains a key campaign issue, in spite of the candidates' occasional efforts to slide around it and the closer-to-home impact of a sagging economy on voters' decisions.

Two milestones are approaching rapidly. The first is the five-year anniversary next month of the war's start. The Bush administration still has not succeeded in tying the Iraq invasion to making Americans safe from terrorism. The likely impact is the contrary: Iraq is on-the-job training for aspiring terrorists in fighting American troops.

The other coming milestone is 4,000 U.S. deaths. The total now stands above 3,970. Financial cost to the United States has been nearly $500 billion, but the real burden must be measured in opportunity cost -- what the country could have done with that money if it hadn't been spent on a misbegotten war. U.S. infrastructure requirements just to maintain surface transportation are estimated to run above $225 billion per year for the next 50 years.

President Bush and likely Republican nominee Sen. John McCain maintain stoutly that the United States is succeeding in Iraq. The "surge" has improved security in Baghdad, but long-term prospects are uncertain. The Pentagon is projecting that, after the surge is completed this summer, there will still be 140,000 U.S. forces in Iraq, 8,000 more than when it began in January 2007.

It is worth noting that the past six months, the period during which the surge is to have accomplished the most for Baghdad's security, has corresponded with a truce on the part of the Shiite Mahdi Army of cleric Muqtada al-Sadr, the Iraqi with the largest number of armed supporters. He has, fortunately for the United States, extended his forces' truce for another six months.

There is no question that Muqtada al-Sadr is simply waiting out the Americans and that he, at 34, can wait decades if he likes.

That means the agenda for the United States during the election season and through the inauguration next January remains the same: Insist that the country begin and pursue systematic withdrawal of its troops from Iraq, bringing an end to Mr. Bush's costly adventure. None of the candidates' words will or should change that objective, which is essential to putting America back on the right path.