I don't know that I buy them stopping the Sentinel program or something similar.
I mean, yea they stopped Mystique from killing Trask, Trask got arrested for hawking his wares to the Soviets and North Vietnamese, and Magneto turned his big day into a fiasco, but if Mystique assassinating Trask was enough to convince the government of the need for such an anti-mutant program, how is Magneto destroying RFK Stadium and the White House, and trying to assassinate President Nixon not enough?
I mean, I can see how the Sentinel program itself would be scrapped, but all that and the government didn't put any other anti-mutant programs into action?