Different assessments of the effectiveness of the 2007-2008 American troop surge in Iraq have become a campaign debating subject.

Announced by President Bush in January 2007 when the level of violence in Iraq had dispelled any impression that the war might be over, the surge -- raising the total of U.S. troops in Iraq by nearly 36,000 in the end -- had ambitious goals.

The first was to bring the level of carnage down. The second was to improve security so that the occupation government of Prime Minister Nouri Kamal al-Maliki could apply itself to putting in place stronger measures of governance. These would constitute, in theory, the sort of government to which the United States could credibly turn over authority, end the occupation and leave.

The argument now in U.S. politics is whether the surge worked. It has worked, if one sees the increased number of U.S. troops in Iraq as the reason for the reduction in violence that has taken place in recent months. It would be hard to imagine that the addition of 27 percent more American troops would not result in improved security.

On the other hand, Iraqis now are fully aware that America is probably at the front end of a countdown to withdrawal from Iraq. The White House has spoken of a "general time horizon" for reducing American forces there. If the likely Democratic candidate, Sen. Barack Obama, wins, there is virtually no doubt that he will begin bringing U.S. troops home. If the probable Republican candidate wins, of course, the war will likely continue.

In any case, it is hard to imagine that anyone believes that the Iraqi insurgents are not capable of ratcheting up the violence again anytime they like. The surge thus worked, in a sense, perhaps, for now.

The sense in which the surge seems to have failed is that the Iraqis have not taken advantage of the period of relative peace that it may have brought to put their house in order for eventual orderly rule. For example, there is still no oil bill, determining how the country's oil revenues, its principal source of income, will be divided among its groups.

The Iraqi government's latest punt was on the subject of a law under which to hold provincial elections, already delayed and considered to be an essential building block to serious government. The Kurdish members of parliament walked out and the bill seems to be stalled for the summer.

So, what did the surge amount to? The American troop level went from 132,000 to 168,000 and is now back to 140,000. American deaths in Iraq rose by more than 1,100 during the surge to a current 4,124. The cost of the war now stands at $540 billion. The surge was probably useful, to stop the increase in violence taking place when Mr. Bush announced it from becoming a rout, unless one sees Iraq ending ultimately like Vietnam.

Whatever happens next, it is fair to take comfort from the fact that the level of U.S. forces in Iraq, with the end of the surge, is going down rather than up. The real withdrawal still remains to be achieved, whether the 2007-2008 surge is considered in balance to have been useful or pointless.