Both sides -- Republicans and Democrats -- have drifted significantly leftward.
George W. Bush was just following in the footsteps of the "Great Communicator" who accepted the premise that in order to finance the destruction of Soviet Communism, he had to allow a Democrat social spending panty raid on the treasury. In President Bush's case, he had to keep up funding for the War on Terror, without Democrat complaints that the money could be better spent on items like prescription drug coverage here at home. The gambit didn't work, of course, but he had to try and win one for the Gipper('s memory).
Somewhere Karl Marx has a big grin on his face doesn't he?