Senior Islamic Jihad Leaders, Khaled Al-Batsh (R) and Khader Habeeb (L), during a press conference in Gaza City. (Wesam Saleh, Maan News)

This article was originally published in the San Diego Union-Tribune and is republished with the author's permission.

Federal prosecutors suffered a stinging rebuke recently when a Florida jury refused to convict four Palestinian defendants on any of 51 counts alleging that they supported terrorist acts by Palestinian Islamic Jihad. That organization employs violence against continuing Israeli colonization of Palestinian lands and ultimately aims to replace Israel with an Islamic state.

PIJ has never deliberately targeted Americans, nor launched attacks outside of Israel or the Occupied West Bank or Gaza Strip. Nonetheless, some American citizens have been killed in PIJ attacks, including Alisa Flatow, who tragically lost her life on April 9, 1995, near the Israeli settlement Kfar Darom. She had been living in Israel at the time.

University of South Florida computer science professor Sami al-Arian and co-defendants Sameeh Hammoudeh, Ghassan Ballut and Hatim Fariz faced evidence accumulated over more than a decade of telephone wiretaps and other surveillance techniques - 20,000 hours worth. When the indictments were initially announced in February, 2003, then-Attorney General John Ashcroft trumpeted the case as proving the vitality of the Patriot Act to the "War on Terror."

That act eliminated the institutional wall separating evidence gathered by intelligence agencies under the Foreign Intelligence Surveillance Act and that gathered by law enforcement agencies for traditional criminal prosecution. Under the Fourth Amendment to the U.S. Constitution, searches for criminal evidence must be supported by "probable cause" - an amorphous term, but one given teeth through court interpretation - while searches directed at foreign espionage need not be. Until the 2001 Patriot Act, intelligence agencies were barred from sharing FISA-gathered information with law enforcement agencies, for fear that the latter would use that information and thereby indirectly circumvent the provisions of the Fourth Amendment.

After five months of testimony and 80 government witnesses, the Florida jurors were clearly unimpressed. The defense consisted of the phrase: "The defense rests, as the prosecution has not proved its case." Jurors acquitted al-Arian on eight of 17 counts, and were unable to reach the required unanimous verdict on the rest. Two other defendants were fully acquitted, while the third was acquitted of 25 of 33 counts, the jury deadlocking on the remaining eight counts. The split on most or all of the deadlocked counts was reportedly 10-2 for acquittal.

Normal double jeopardy principles do not apply where a jury has "hung" or failed to agree on a verdict; instead, prosecutors have the right to retry the defendants on the "hung" counts. The prosecution obviously failed to draw direct links between the defendants and actual acts of violence, thus leaving jurors pondering the dividing line between criminality and protected political speech.

Prosecutors should think long and hard before spending more U.S. taxpayer money in pursuit of convictions in this case, which was fraught with political overtones from the outset. This was in part a consequence of the very process by which "terrorist organizations," and thus the criminality of support for them, are defined. While Congress has deemed certain acts in support of terrorism as criminal, our law permits part of the executive branch - the U.S. State Department - to designate which groups are "terrorist." This is inevitably a political decision.

During the '90s, when PIJ was dubbed "terrorist," our government allocated millions of dollars to support Iraqi opposition groups that engaged in car bombing campaigns in southern Iraqi cities killing hundreds of Iraqi civilians. Iyad al-Alawi, the head of one such group, the Iraqi National Accord, is the U.S.-supported prime minister of Iraq today. It is further well known that prominent American politicians, such as Ted Kennedy, vocally supported the Irish Republican Army during a period when its tactics were as bloody as those of PIJ.

Perhaps one lesson from this costly failure is that we should be more circumspect in prosecuting "other people's terrorists" - groups that do not deliberately target American victims. That way we would be less prone to run afoul of the tenuous line between one group's freedom fighter and the other's "terrorist."

Sami al-Arian was subjected to brutally harsh conditions of pretrial detention, and was fired from his university position on mere accusation. He has paid enough, and it is time to set him and Fariz, the remaining co-defendant, free.

George Bisharat is a professor of law at Hastings College of the Law in San Francisco and writes frequently on law, politics and the Middle East.