Ezra Klein and Representative Jim Cooper (D-TN) float the idea that members of congress should be paid for performance, though of course neither of them can say exactly what that would mean.
Here’s maybe another way of thinking about it. Most politicians care about money, obviously, but the job tends to select for people who at the margin are primarily motivated by a desire to win elections. And for a president, this builds in a kind of performance pay. The better the economy does, the better your chance of getting re-elected. The more troops die in wars, the worse your chance of getting reelected. Now of course there’s more to life than casualties and short-term GDP performance, but these criteria are nothing to sneer at. And in a political system like the United Kingdom’s, all the oars are pulling in the same direction. David Cameron hopes things go well, in which case he’ll get re-elected. Labour gets to whine and hope its criticisms of Cameron turn out to be prescient, but what they say doesn’t actually matter.
The American system’s not really like that. Barack Obama is held responsible for the overall performance of the US economy in a way that’s way out of proportion to his actual influence over the legislative process. Meanwhile, members of the minority party in the senate and guys with safe House districts have a kind of power without responsibility.