The difference between Romney and Newt is not only abortion. The establishment of the Republican party wants Romney because just like him they talk a good conservative show and never do anything. They are afraid that Newt will do what he did in the 90s, the public will not accept the cuts that are necessary to save the nation from financial disaster, and they will lose the ability to protect the fat cats.
Look at the Republican party record on conservative values. They yak yak about abortion, balancing the budget, etc, then we give them a majority in the house (where spending bills originate), they fund planned parenthood and pass record setting deficit budgets, lie to us about how much they have cut... and slyly claim the devil dems made them do it by threatening to shut the gov down.
I say all conservatives should dump the repub party, and vote libertarian this year. We will lose the presidency but at least we will have a chance in the next one of actually getting something done, by forcing the Repub party to either nominate a conservative or LOSE for sure.