As Ezra points out, the Republican governors ask "how high" when the GOP base says "jump". Folks on the left complain - often rightly - that Democratic pols feel more pressure from the media than from their base and it causes them to do stupid things in Washington like vote for the Iraq War or for Bush's tax cuts that helped ruin the economy. But the GOP fealty to their base is the flip side of this phenomenon. The Republicans are all about appeasing what turns out to be a shrinking portion of the population, the same people who were the dead-enders who supported Bush and were convinced that immigration was the most important issue ever (a racist push that has likely permanently pushed Hispanics into the Democratic column).
I hated the cautious namby-pambyism of the 2000-2005 Democrats, but the way the Republicans are run now its as if after 2000 we just let Dennis Kucinich run the party. I like Rep. Kucinich but its safe to say that his views on the issues are considerably to the left of the average Democrat, let alone American. The GOP has no such moderating influence - there's no reward in being a moderate Republican nowadays - just check out the hate mail people like Susan Collins and Arnold Schwarznegger get.
The Republican party remains the party of George W. Bush. And that's good... for Democrats.