Reagan at least admitted that it was a mistake.
Bush isn't proposing amnesty.
In all but name he is. There is no enforcement mechanism in his proposal to repatriate blue card holders at the end of their stay. These are people who entered illegally and stayed for years. They have no reason to leave and therefore no motive to abide by a law without a means of enforcement.
They won't vote Republican either.
It is a proposal. It is up to Congress to figure out the specifics. This isn't an Executive Order you know.