Surviving Nixon, surviving Bush
The Republican Party is seeing some pretty tough challenges in the recent Bush scandals that are coming to light. It's easy to think that they'll cope with them, that if you consider that the Republican Party survived Nixon, they can survive this. But the thing is, the Republicans didn't survive Nixon. Nixon destroyed the party, and it could only continue to exist by recruiting new members somehow. Since moderates were too disgusted by what Nixon had done, they turned to evangelicals and bigots—groups whom they'd shunned earlier. Classic progressives like Nelson Rockefeller and George Romney were squeezed out of the party, while dirtbags like Nixon and Reagan took charge and sold out the future of the country.
The Democrats, on the other hand, had no problem "surviving" Clinton because under Clinton, there wasn't a genuine scandal, like Watergate, for example. While Ken Starr was convicting Clinton of getting a blow job, Clinton's popularity stayed strong, which was evidence that most people didn't think what had happened was egregious. Bush, on the other hand, is suffering as the flashlight is being shined on the cockroaches of his party. People know, on some level, a real scandal when they see one. And boy, do they see one.
Bush: worse than Teapot Dome, worse than the Tammany Ring, worse than Iran-Contra, and worse than Watergate. History will not remember Bush well.