But the test comes at an inopportune moment. The U.S. administration was hoping its outreach to Iran without preconditions would result in the Iranians' helping us to calm the Shiites in Iraq (and some of our enemy in Afghanistan).

Whether that was ever plausible we never will know. Now, instead, with the Iranian regime shooting down its own people in cold blood, President Obama has been pulled into a nasty exchange of angry and rude words with Iranian President Mahmoud Ahmadinejad -- from whom, therefore, we cannot reasonably expect help as we try to extract ourselves from Iraq and build up in Afghanistan.

I am struck by the potentially appalling irony that overhangs the president's decision this week to go forward with the removal of troops. G.W.F. Hegel, a great philosopher of history, believed that history is ironic and that every historical circumstance contains the seeds of its own destruction.

Consider that it was Obama's central message during the presidential primary campaign that President Bush had made a strategic error by precipitously withdrawing troops from the war in Afghanistan -- the good and necessary war -- in order to provide troops for the unnecessary and ill-considered Iraq war. While the general election hinged on many issues, it was Obama's early and consistent opposition to the Iraq war and support for the Afghan war that gave him traction and eventual victory over Hillary Clinton.

Now President Obama is honoring his campaign pledge to systematically and promptly withdraw American troops from Iraq and send them to Afghanistan. But now it is the Iraq war and (until now) impending peace that looms large as a potential strategic advance for Western and peaceful interests in the Middle East. (Did the democratic Iraqi example encourage the Iranian democracy fighters?)

And it is the Afghan war that seems without clear purpose or likelihood of success and that is draining currently needed troops from the Iraq theater of operations.

I don't know whether history is ironic. It would seem to have a "fearful symmetry." It is certainly merciless.