David Cameron's Conservatism responds to local British conditions. It's not an export product. But there is at least one big lesson that Americans could learn from him when the Tea Party finally ends: yes, a party must champion the values of the voters it already has. But it must also speak to the voters it still needs to winWhy would Republicans want to learn how to blow a 20%+ poll lead? Whilst speaking to the voters concerns is one thing, surrendering the ideological argument to them is foolish. It is one thing to appeal to moderates, it is quite another to throw mud at your base in order to suck up to people who will never vote for you.
In Australia recently, the Liberal Party (the main centre-right party) deposed its moderate and media friendly leader, Malcolm Turnbull, last year and replaced him with the "extremist" and less compromising Tony Abbott. The result hasn't been what the pundits had predicted, as the Liberals have rebounded strongly in the polls.
This doesn't mean that it always right to select less centrist candidates but that it isn't always a mistake.