During their opening statement in Sami Al-Hussayen's trial at the federal courthouse in Boise, Idaho, prosecutors put a new spin on the slippery concept of "links to terrorism." The Idaho Statesman reports that they "displayed a chart" showing how a Web site that Al-Hussayen had helped maintain "could eventually access 20 other sites with ties to radical organizations."

Talk about guilt by association. Given the interconnected nature of the World Wide Web (they don't call it a "web" for nothing), just about any site with hyperlinks "could eventually access" something sinister.

That does not mean Al-Hussayen, a 34-year-old Saudi whom the government accuses of supporting terrorism by creating and maintaining Web sites for various Islamic organizations, is the man he claims to be: a peaceful computer science student who rejects terrorism and was simply trying to promote Islamic outreach and education through volunteer work. But judging from the evidence the government has presented so far, he could be.

Al-Hussayen's trial, which is expected to conclude by June, illustrates the difficulty of deciding when "links to terrorism" should be treated as a crime. It also shows the importance of maintaining an open, adversarial process for judging whether someone is guilty of siding with terrorists—a timely reminder as the U.S. Supreme Court considers whether the Bush administration has the authority to make such determinations secretly and unilaterally.

Al-Hussayen, who was arrested in February 2003 while working toward a Ph.D. in computer science at the University of Idaho, is charged with providing "material support" to terrorists, a crime that was broadened by the PATRIOT Act to include "expert advice or assistance." As Attorney General John Ashcroft summed it up, "Al-Hussayen knew and intended that his computer services and expertise would be used to recruit and raise funds for violent jihad around the world."

Since what Al-Hussayen did is not really in dispute, his guilt hinges on what he "knew and intended." But the government's evidence that he deliberately aided terrorism consists almost entirely of online statements by others that he says he neither created nor endorsed.

"The core of the case," the prosecutors say, is four fatwas (religious decrees) that were posted at www.alasr.net, a site that Al-Hussayen helped maintain. The fatwas, which appeared in 2001, defend suicide attacks on "the enemy" as consistent with Islam.

But Al-Hussayen—who as a local Muslim leader released a statement after the September 11 attacks condemning "vicious acts of terrorism against innocent civilians"—insists he does not agree with those fatwas. They were among thousands of postings that he handled for various sites, which also included articles arguing that terrorism is contrary to Islam. Prosecutors concede that "much of the content of the Web sites was seemingly benign."

Likewise, the government holds Al-Hussayen responsible for incendiary comments by participants in a Yahoo! e-mail group devoted to Chechnya. Although Al-Hussayen was listed as one of several moderators for the list, he served that function only 17 times over three years and deleted just one message during that time, a pattern that seems to indicate inattention rather than agreement.

In any event, as with the fatwas, the government is prosecuting Al-Hussayen based on his presumed approval of statements that, however reprehensible, would be protected by the First Amendment if he had written them himself. Similarly, his alleged support for terrorism includes his donations to the Michigan-based Islamic Assembly of North America, which has not been classified as a terrorist group and continues to operate as a legally recognized charity.

Prosecutors say Al-Hussayen's personal views are irrelevant. All that matters is that he knowingly provided "expert advice or assistance" that aided terrorist recruitment and fund raising.

But given the broad meaning of "expert advice or assistance" and the difficulty of getting inside people's heads, the same charge could be leveled against anyone who performed professional services for a group that the government believes has terrorist ties. Under the Justice Department's reading of the law, Georgetown University law professor David Cole told The New York Times, "Somebody who fixes a fax machine that is owned by a group that may advocate terrorism could be liable."

Al-Hussayen may face a formidable task in convincing a jury that he did not know and intend what the government says he did. But given the way the Bush administration treats terrorism suspects it designates as "enemy combatants," he is lucky to have the opportunity.