9/11 military trial best option left

Putting self-proclaimed 9/11 mastermind Khalid Sheikh Mohammed on trial before a military commission at Guantánamo Bay is a stark setback for President Barack Obama. But he had little choice. It's been almost a decade since 9/11, and Mohammed and four co-conspirators must finally be brought to justice.

A civilian trial for Mohammed would be the better course. The world should see him judged on the evidence with all the protections of the U.S. Constitution. Hundreds of terrorists have been convicted in federal courts since 9/11, while only a handful have been adjudicated in military commissions hamstrung by constitutional issues.

But when the administration announced in November 2009 that it would try Mohammed in federal court in Manhattan, the public outcry was deafening. Support for the trials among New York's elected officials evaporated, and Congress blocked the transfer of any prisoners from Guantánamo to the United States.

Obama ceded too much ground. He was left with few options, none of them good. He could imprison Mohammed indefinitely without trial, which is troublingly un-American. Or go with a military trial, which is now the only acceptable way forward.

The military commission's rules have been rewritten since they were established by President George W. Bush. Trials will test whether they now pass constitutional muster. Even under that cloud, military trials are better than indefinite legal limbo.