The government’s charges against Osama bin Laden’s son-in-law looked pretty thin. Washington was basically claiming that the Kuwaiti imam had made a few inflammatory speeches — one praising the September 11 attacks and another warning that more attacks on tall buildings were soon to come. It didn’t sound like much, given that the charges were providing “material support” for terrorism and conspiring to kill Americans.

But less than a year later, 48 year-old Suleiman Abu Ghaith stands convicted on all counts, following a jury trial in a U.S. federal court. Over the three-week trial the government managed to convince a jury that the cleric’s actions — giving a handful of speeches for al Qaeda, some on camera seated next to bin Laden — made him responsible for the September 11 attacks, the 1998 U.S. embassy bombings in East Africa, and the 2000 bombing of the U.S.S. Cole, a Navy ship docked in Yemen. Abu Ghaith didn’t even make his first videotaped speech until September 12, 2001.

It’s an odd quirk of U.S. conspiracy law. If someone joins a conspiracy, though it may be years after it started, he’s still liable for all the murder and mayhem his co-conspirators caused, even if it was long before he came along.

That’s what happened to Abu Ghaith. The jury may have believed he only gave a few speeches helping al Qaeda after the September 11 attacks, which is when he says he first met bin Laden, but Abu Ghaith is legally responsible for every American who bin Laden and his compatriots killed before that.

Some people assert that the U.S. conspiracy law is too broad. More surprising is that some people think the U.S. federal courts are too lenient.  Suspected terrorists should not be granted “the same rights as U.S. citizens,” insisted lawmakers such as Representative Mike Rogers (R-Mich.), chairman of the House Permanent Select Committee on Intelligence, when Abu Ghaith was arrested.