Remember Bush's half-hearted attempt to introduce some tiny steps toward making social security solvent? The AARP sent some of their plants to disrupt the initial hearings and he packed up the tents and retreated to the tall grass, never to bring up the topic again.
Compare and contrast that to the congressional smack-down he got on amnesty and recall the first words out of Karl Rove after the 2006 mid-term shellacking a wonderful opportunity to reintroduce comprehensive immigration reform. Which, if you recall, they promptly did.
Romney does not have a conservative bone in his body, and as is typical for him, he was always uninterested in any form of border control until he had that stroke during the primaries, when he became the opposite of who he was his first 60 years.
Romney was every bit lenient on immigration until the ‘new Mitt’.