A botched bomb attack appears to have unraveled one of the most mysterious terrorist organizations in Europe. The Nov. 17 group had operated with impunity in Greece for 27 years; it seemed impenetrable and untraceable. But the premature detonation of a bomb last month gave police the leads they needed to roll up the leftwing group.

The arrests go a long way toward restoring the credibility of the Greek security forces -- a necessity in the runup to the 2004 Olympics in Athens. But suspicions about Nov. 17's connections to the Greek government must also be cleared up. Nov. 17 has been a scourge for decades. Athens' political credibility depends on discovering how and why it survived.

Nov. 17 took its name from the day in 1973 when the Greek government sent tanks into the Athens Polytechnic to crush a student uprising against the military junta; dozens of students were killed. The group debuted with the 1975 murder of Richard Welch, the U.S. CIA station chief in Athens. From then, it combined anti-Americanism -- payback for Washington's support for the rightwing junta that governed Greece from 1967-1974 -- with nationalism. It launched hundreds of attacks against government offices, firebombed foreign businesses and assassinated foreign diplomats as well as Greek politicians and businessmen.