How about both at the same time?

Sen. John McCain, R-Ariz., wants to keep U.S. forces in Iraq; Sen. Barack Obama, D-Ill., basically wants to evacuate them.

On Monday, reports said violence had dropped to a four-year low in Iraq. That was obviously good news. The same day, reports announced that two more U.S. troops had been killed in yet another bomb attack. That was obviously bad news.

Also on Monday -- Memorial Day in the United States -- the total number of U.S. soldiers killed in Iraq since the start of operations to topple Saddam Hussein on March 19, 2003, was reported to have reached 4,082. No surprise at that slow but steady increase, and the slowness of the rise is obviously encouraging news, but hardly a cause for rejoicing.

Over Memorial Day weekend Grand Ayatollah Ali al-Sistani, the most senior Shiite Muslim religious authority in Iraq, was first reported by unnamed "sources" allegedly close to him to have advocated resistance to U.S. forces remaining in Iraq. That obviously would be bad news if it was true, but within a couple of days other "sources" close to the grand ayatollah clarified his position and said Sistani had said no such thing: They said the grand ayatollah was advocating non-violent resistance rather than anything more dramatic and deadly.

According to a report on Iran's al-Alam TV Sunday, Sistani, while not calling for active, direct violent opposition to U.S. forces, opposes the current terms of the Status of Forces Agreement that U.S. diplomats are seeking to conclude with the Shiite-dominated government of Prime Minister Nouri al-Maliki in Baghdad.

Bush administration officials and American pundits have repeatedly stumbled badly in their efforts to understand Sistani and his positions. Sistani has major influence as the surviving most senior ayatollah in Iraq. But he is not a charismatic figure like the far younger Moqtada Sadr, head of the now-embattled Mehdi army.

The guiding principle of Sistani's character -- so great that he appears to have been marinated in it -- has always been extreme caution. This enabled him to survive the long, deadly years of Saddam Hussein's tyranny.

Sistani has never dared to provoke U.S. forces in Iraq directly, but he has never shown them any special regard or respect either. He has sought to avoid directly meeting with senior U.S. officials and generals as much as he can, and he has long retained his Iranian citizenship.

Pro-Bush administration hawks in the United States have consistently misread Sistani's extreme caution, and even timidity, as tacit support. Doves opposed to the United States retaining a significant military presence in Iraq sometimes have praised Sistani excessively as a wise and shrewd leader with great, even decisive influence in the Shiite community that comprises 60 percent of Iraq's 28 million people.

The reality appears very different from either of these simplistic hawk and dove views. Sistani appears to loathe the continuing U.S. presence in his country but has not dared so far to come out and directly call for its overthrow. His sympathies appear to be pro-Iranian, but he remains exceptionally cautious, even timid in expressing them. These attitudes erode and undermine the influence he is supposed to exercise as Iraq's most senior Shiite cleric.

The difficulty in understanding what Sistani can and will do, and even where he stands, is symptomatic of the continuing confusion and even ignorance of U.S. policymakers about Iraq more than five years after the U.S. military occupied the country.

McCain's suggestion that he and Obama visit Iraq together was obviously made with partisan political gain in mind. But such a joint visit could serve a very important bipartisan national purpose for the American people by acquainting both the Republican and Democratic front-runners for their parties' presidential nominations with important firsthand experience of that troubled country. And such a joint visit also would force the U.S. media to take new, detailed, hard looks at both what is going right and what is going wrong in Iraq. The American public could only profit from that.