The RNC-GOP-Establishment-RINOs or Whatever TF it is, does NOT WANT THE WH! They know it's all going to crash. They want it to be Obama's Fault while they use Romney and the money to win the House and the Senate. The pros call this the "Down Ticket" strategy.
Their theory is foolish. They actually think they can tie up Obama in a sort of replay of the Clinton deal when they got Welfare Reform passed. Obama with his czars and with his contrrol of the executive branch will simply buy the RINOs and complete his plan to bring Socialism to America.
The GOP is passing up a chance to save the country. That's all.
First off, the economic plan of either Santorum or Gingrich would turn the US economy around effectively within four years. That would probably bring back the world economy as well. It would be clear contrast to the failed socialist 0 agenda.
However, if 0 wins another term, the damage to the Supreme Court would likely be irreparable. It would take CW2 to rectify things.