The debate in the Senate last week over when to exit Iraq was disgraceful.

Americans deserve an honest airing of the most important foreign-policy issue facing the country. But this congressional circus had little to do with policy and everything to do with election-year politics.

Democrats looked hapless, and many Republicans were flat-out dishonest. The Pinocchio prize for devious discourse went to Pennsylvania Republican Sen. Rick Santorum.

I'm surprised his nose didn't grow a foot when he claimed a recent Army intelligence report proved Saddam had weapons of mass destruction. The report — released under Republican pressure in the midst of the debate — says about 500 munitions have been recovered in Iraq since 2003 that contain "degraded" mustard or sarin gas.

Mind you, these munitions were picked up in ones and twos and date back to Iraq's war against Iran in the 1980s. There was no operative Iraqi chemical weapons program after 1991.

Such weapons degrade over time. According to David Kay, the head of the U.S. team that hunted for WMD in 2003-04, these gases by now would be "less toxic than most things that Americans have under their kitchen sink." Their "poor condition" was affirmed by intelligence officials in a media briefing.

But Santorum insisted this intelligence proved Saddam had WMD that could have reached terrorists. Such silly claims will only bolster the evidence that U.S. intelligence is being manipulated for political reasons.

Why on Earth would terrorists want old, degraded munitions when much more tempting targets lie within potential reach — like unsafe Russian nuclear storage dumps? Has Santorum been demanding more money to secure Russian nuclear waste?

But let's get back to serious business — the debate over a U.S. troop exit. I happen to believe those Democrats who want to set a timetable now are wrong. But the Republican taunt that Democrats want to "cut and run" is driven more by election considerations than by security concerns.

The White House knows full well that there is a vigorous debate within the U.S. military over the very issue Democrats raised: whether keeping more troops in for longer makes the situation worse or better. These are the military concerns that Democratic Rep. John Murtha hears.

I've heard both sides argued by top officers in Iraq and inside the Pentagon. As one senior military source put it: The big debate is whether drawing down would make the Iraqis stand up sooner. Some say yes — as long as the United States leaves a substantial force of military trainers and advisers along with airpower.

"There are too many troops here now," one senior officer in Iraq told me. "It creates dependency and becomes a magnet for attack." This particular officer would like to see troops cut to 80,000 to 90,000 right now and 20 to 40 percent more in 2006.

Another senior officer argued just as hard for "hanging around longer to give a chance for Iraq's new national unity government to gel, if the goal is to keep Iraq together." I concur.

If we left too soon, Iraq would sink into greater chaos, affecting the entire region. But I believe U.S. troop levels will decrease sharply by 2007, for several reasons.

Republican political pressure for a pullback will grow before the 2008 elections. Moreover, Iraqi officials from nearly all factions say they want U.S. troops drawn down within 18 months. Iraqi national security adviser Mowaffak al-Rubaie wrote in The Washington Post last week that he expected most of the U.S. troops "to return home by the end of 2007."

However, neither Rubaie nor more senior Iraqi leaders want an explicit timeline. Instead, they favor a "road map" for troop reductions that depends on achieving a set of goals for improving Iraqi security. They want dates, but dates that depend on meeting those targets.

So are Rubaie and a hefty segment of senior U.S. brass "quitters"? Or are they more honest than many Senate Republicans?

As for the Democrats, they should stop obsessing over timelines. The Republicans and the Iraqis will set those soon enough.

Instead, Democrats should focus on the issue of competence. They need to convince voters they can handle the Iraq mess better than the White House — whose incompetence made it.

The competence test should be central to any argument over Iraq's future. Would that candidates also had to pass a Pinocchio test when debating Iraq.

Trudy Rubin is a columnist and editorial board member for the Philadelphia Inquirer. Reach her at trubin@phillynews.com.