It's amazing how both accidents produced very different reactions.
The Challenger tragedy produced a much higher emotional reaction but the program wasn't as much reviewed as after Columbia.
After Challenger, the shuttle was replaced and the program continued.
After Columbia, the whole program is transformed.

Is it because of (or thanks to) Reagan's speech after the first catastrophe?
Is it because repairing the O-ring was a lot easier than dealing with the ET's foam?
Is it because it had already been decided not to build a new shuttle anyway?
Is it because two accidents definitely showed how dangerous the shuttle is (in spite of 112 successful flights).

Is it because of time passing and in 2004, LEO had little political appeal while so much remained to be done in the shuttle program in 1986?

I sure hope this won't affect the number of persons going to space.

Raoul