|Doesn't matter who does it, the result will be the same.|
A lot of the attacks of Newt Gingrich have been that he really isn't a conservative he's a big government Republican, or a technocrat who may have conservative ideals but is far too susceptible to solutions that have huge downside government overreach implications. That's the real worry that his opponents are trying to play on. If Mitt Romney is wishy-washy and a say anything faux conservative, Newt Gingrich has too much baggage and is not really conservative either.
The secret if you want to derail Gingrich is in the approach that Ron Paul has towards government. It's not about rolling back Obama's big government progressive agenda and replacing it with another conservative idea, it's about rolling it back and replacing it with nothing from government.
That may be the best approach in derailing the Newt campaign - point out that he's replacing liberal government meddling with his own brand of meddling. We'll see if anyone tries that argument on Newt. It could be very effective.. It aligns with a lot of the Ron Paul framing of the issues; government is too big, it's gone to far, so make departments and regulations disappear. Of course Ron Paul does have some untenable positions on foreign affairs, but he is right about government over reach. But if you start from his framework there is some pretty simple questions one could ask of Newt that might force him to box himself in while responding.
NOTE: I'm not about derailing Newt. I think he has the best chance of beating Obama. He's not the most conservative candidate in the race (although I'd say more conservative than Romney), but I do think he may have the most potential to win the general election based on his debating strengths. The conundrum is still electability versus most conservative possibility. I don't think that equation has been worked out yet for a lot of voters.