Economic growth (or lack of), not party control, drives deficits

Ezra Klein:

What you're seeing there is that it's not the composition of the government, but the growth of the economy, that drives the deficit. Wide gaps open up during the 1973, 1981, 1991 and 2008 recessions, and they close as the economy recovers. That's holding true now, too: The annual deficit fell by $125 billion between 2009 and 2010 -- the single largest drop in our history.