It's no much a move to the left,
as it is a vote against a party that's lost its way. The GOP needs to refocus on its core values and get back on the straight and narrow. Bush's massive spending spree over the past several years, and total lack of interest in securing our borders have done a lot to hurt the party this election cycle. Bush talks alot about conservative principles, but he doesn't walk the walk very well. Newt needs to come back and put some discipline back into the party of small government and middle class values.
Controlling spending, a sound and viable energy policy, and border security are the issues that would've handily won this election for Republicans. On those counts, Bush and McCain both blew it.