The oldest saw in politics is "Power corrupts". That isn't always talking about personal venality, although it often is; more generally, it means that, the more power you have, the more prone you are to hubris. It's been pretty clear for a while now that this was going to be the Achilles heel of the Republican leadership, but it's coming to the fore rather quickly.
Their problem is their strength. They put a huge amount of effort into getting lots of Republicans elected to both the House and Senate. But they seem to have fallen prey to the assumption that those Republicans were homogenous -- lots of little soldier-fanatics who would follow the leadership's agenda. But of course, that isn't true. Especially the ones who come from blue states, or from borderlands, tend to be much more moderate than the hard red-state core. Their agenda doesn't match the leadership's agenda; indeed, their agenda is often greatly at odds with that of the leadership.
Thing is, the incumbency effect is very harsh on the Republican assumptions. They've relied on using a very strong whip. "If you want to get elected, obey us." "If you want collective power, obey us." For the thoroughly red states, that carries a lot of influence: the Republican groupthink is strong, and it's hard for an apostate to stay in office. But just the opposite is true of the bluer states. For a Republican official to stay in office in this region, it's probably *better* for their career to be seen as bucking the power structure. In a country that increasingly self-identifies as "independent", mavericks can get a lot of respect. And it's not hard for a respected incumbent to stay in office.
Tom DeLay may be the first victim of this, and it's hard to imagine a more appropriate one. I'm sure that he's alienated a lot of the moderate Republican senators, and now his political life is in their hands. It'll be interesting to see how they go on this. There's a sort of prisoner's dilemma involved. From a power POV, holding together is currently a source of considerable strength. (The neocons are often referred to as "crypto-fascists", and there's much truth in that.) But as soon as things begin to fall apart, it is *much* better to be an outsider -- to be one of the "good guys" exposing the excesses of the leadership, rather than one of the people being attacked. I suspect that a number of Senators are making exactly this political calculation right now.
The even more interesting question is what follows. The whole tone and style of this administration has been one of unshakeable loyalty -- you obey orders and don't publically disagree with the leadership, and you get your cookies. *If* that begins to crack (and it's not yet clear whether it's going to do so or not), it could turn into a feeding frenzy, as everyone realizes that loyalty is no longer safe. The major media have been utterly supine, largely because they bought into the line that the administration is calling all the shots. But if it begins to look like that's not the case any more, the media outlets wind up with much the same calculation as the Senators. Once the avalanche truly starts, the best place to be is up on top of the hill, rolling the boulders down on everyone else...