Should pastors stay out of politics?

In a fascinating interview with Christianity Today, 92-year-old Billy Graham shared some candid thoughts on aging, evangelicalism, the past, and the future.  

When asked if he would do anything differently, Graham responded: 

Yes, of course. I'd spend more time at home with my family, and I'd study more and preach less. I wouldn't have taken so many speaking engagements, including some of the things I did over the years that I probably didn't really need to do—weddings and funerals and building dedications, things like that. Whenever I counsel someone who feels called to be an evangelist, I always urge them to guard their time and not feel like they have to do everything.

I also would have steered clear of politics. I'm grateful for the opportunities God gave me to minister to people in high places; people in power have spiritual and personal needs like everyone else, and often they have no one to talk to. But looking back I know I sometimes crossed the line, and I wouldn't do that now.

This strikes me as good advice for all pastors, and I hope many will take it to heart. I sense from the rest of the interview that Graham is concerned about evangelicalism’s preoccupation with power and politics, which is indeed driving a lot of young people away and muddying the gospel message.  May all of us--liberals and conservatives and everyone in between--lend an ear to a man who's been at this for a while. 

Do you think pastors should stay out of politics? Will evangelicalism ever break away from its association with politics?