Andrew: part of the problem for the Tories is that Britain uses that Parliamentary/Party List system. That enables the party apparatus to maintain strong control over the elected party membership. It’s not like that here – national political parties are weaker, they can affect but can’t control the outcomes of primaries and this tendency has been increased by the effects of the McCain-Finegold campaign law, which tends to push issue-oriented advertising out to independent single-issue organizations.
I think these differences allow critical extra flexability in our political choices.
The commenter upthread that mentioned the 1994 has a real point: That mid-term congressional election was a huge repudiation of both President Clinton’s policies *and* the moderate Republican establishment of the time, who were mostly content to get tossed bones from the prior Democrat (congressional) majority. It shows that a large enough bloc of organized and determined voters can push a party in a desired direction even against the will of the people nominally in charge. Another example of this on the opposite side is the successful efforts of the nutroots in pushing the dems way further left – to the point of being way too extreme in the general election (i.e. the Liberman debacle).
So, I don’t think the situation is necessarily the same.
P.S. I prefer it our way too. 
