Clearly the govt under Clinton and his administration were most culpable but the roots go back to the Carter administration.
People like Louis Freeh and even Richard Clarke have said some interesting and not very favorable things about the Clinton administration's handling of the terrorism issue. Freeh said that Clinton wasn't serious about islamic terrorism because he was chasing a right wing boogyman who didn't exist. Clarke wanted to investigate middle eastern connections to the OKC bombing but was shut down.
Clinton ran that right wing boogyman menace issue to a successful re-election.
At its worst, he had the FBI wasting resources going after non-existent right wingers who were supposedly setting fire to minority churches. And that is in the later half of the 1990s when the terrorism is ramping up.