"Did Republicans deliberately crash the US economy"?
It is not that simple an answer. Yes, the Republican party leadership, as it is, did state that their number 1 priority was to make Obama a one term President http://www.tnr.com/blog/jonathan-cohn/96591/mcconnell-villain-who-me. So, the tactic they have adopted is to block him at every chance they get regardless of the outcome. Thusly, they make demands they know he will not agree to on every issue they can. Examples are the extensions of tax cuts for the middle class (they tied this to extending tax cuts for million/billionaires), extending the debt ceiling (they tried to get him to cut benefits to medicare/schools), the Jobs Bill (they want massive cuts to medicare/schools extension/increase of tax breaks to big businesses and deregulation of environmental laws). However, Republicans do this because their ideology. They believe that government should be smaller and that industry should be more of the guiding force in social policies. They believe in a trickle-down economic philosophy and loosely regulated capitalism. The question comes down to whose philosophy is accurate: a larger more involved government or a scaled down government with a hands off approach. If you look at what is happening in the world, countries with austerity doctrines are economically and socially hurting right now.
Exactly how bad was the Carter administration?
Not nearly as bad as the Reagan/Bush era - and you've seem what Bush II has done..... OBAMA 08