Banks. And Jobs.
While the absolute level of unemployment does have an impact on elections, the 1934 midterms show that change in unemployment is the more important number. If things are at least headed in the right direction, Dems will get some credit. Past that, it's time to
Update: right, failing to pass financial reform because you can't get past those bastards, given a session where there were in fact some accomplishments elswehere is, arguably, a better situation electorally than passing a watered-down bill. So, allow me to revise and extend.