Proposing to gut Medicare has been politically disastrous for Republicans, and it was pretty obvious that it was going to be a disaster even before they voted on it. So why did they do it? Jonathan Bernstein and Jon Chait offer a few possible reasons:
Well, sure, I guess it could be any of those things. But Jon Chait almost certainly nails the real reason at the end of his post: "I think Republicans more likely just got caught drinking their own Kool-Aid about how the public agrees with their vision."
Yep. It's the nature of political parties to overreach now and again, but usually they learn from their overreaching. Democrats, for example, have wanted to pass universal healthcare for decades, but they've learned from their losses and introduced steadily more moderate plans each time around. Eventually they finally passed one. But Republicans never seem to get it. They win a big victory (or even a not-so-big victory) and then see sugar plums dancing in front of their eyes when they read the poll numbers. America is a conservative country! Now let's cement their support by being real conservatives!
But America, as always, is ideologically (moderately) conservative and operationally (moderately) liberal. This hasn't changed much since the Nixon era, but Republicans just can't seem to wrap their heads around it. So Ronald Reagan implodes over Social Security in 1982, Newt Gingrich implodes over Medicare in 1995, George Bush implodes over Social Security in 2005, and the tea party Republicans implode over Medicare in 2011. Americans, in the least surprising news ever, still don't trust Republicans to screw around with Medicare or Social Security. Even Republicans don't trust Republicans to do it. Probably it's because Republicans have hated both programs from the beginning and keep trying to wreck them every time they get their trigger fingers anywhere close to the levers of power.
What makes this even weirder is that in just the past decade Republicans have helped their political cause by standing up for Medicare: first in 2003 when they passed the prescription drug plan and then in 2010 when they won a big House majority by beating up Democrats for cutting Medicare. But despite all this, they still don't get it. They're still convinced that someday Americans are going to blink their eyes and suddenly agree that Social Security and Medicare are liberal boondoggles that need to be privatized and slashed. It's just an astonishing unwillingness to accept reality.