Given the final poll numbers, it seems likely that Massachusetts Democrats will wake up tomorrow wondering why they didn’t work harder on Martha Coakley’s behalf. It’s a fascinating psychological phenomenon that reverses the usual pattern. As Daniel Gilbert describes in Stumbling on Happiness, people tend to overestimate the extent to which positive or negative events will change their future happiness. But in politics, members of the majority party tend to become disillusioned until some election defeat spurs them again to action. In other words, they underestimate how upsetting an opposition party victory will be. Democrats experienced this feeling after the 1994 election and are likely to do so again in November 2010 if the Massachusetts race doesn’t wake them up.