6 months - I predict a constant deterioration of America's economy this year, and no matter how hopeful they were of Obama, when people keep losing their jobs and their homes, they're gonna start getting pissed. Actually, I don't think it would matter which political party was elected president for those 6 months. Democrats are promising the New Deal which won't help, Republicans would continue with massive spending and bailouts which wouldn't fix things, and Libertarians would advocate they that we need to go through temporary painful withdrawal, which would help but would take time for people to feel the benefits (and Libertarians would also have to convince Congress to drastically cut spending, which would be a battle that requires more time).