They jump ship when it’s politically necessary for them. It’s always good news for conservatives.
That's why it's more important to get the public on our side of the issues than it is to win elections. Like Newt proved in the '90s with welfare reform, if you get enough of the public to back you, the Democrats will capitulate. It's a democracy and they don't want to lose power. Even if Obama is reelected, we can still seek to get veto-proof majorities to go around him when we have the kind of support that these two issues have.