I agree.
If he's going to be President, this will only work if conservatives DON'T gloss over Newt's foibles and failures and, rather, serve him strong notice that he OWES US this time and we WILL hold him accountable.
I totally agree that Newt, unlike Romney, would be susceptible to powerful pulls from the right. Does that mean he has less of a "tethering?" I dunno. I think Bush was completely tied to one idea, namely that he had to protect the U.S. from foreign attacks at all costs---and that led him to do all sorts of other un-conservative things. Reagan's #1 goal was destroying communism, and that led him to sign off on big-deficit budgets and even to ignore his own policy of no negotiations with terrorists. But he achieved his goal.
I don't think President Newt would ever compromise the safety of the U.S. militarily, nor would he (generally) do anything to harm the U.S. economy. I do think that without proper pressure, he'd cave to the global warming crowd and the single-payer crowd. But he can be pushed and pulled and reasoned with. Romney can't because he is firmly "tethered" . . .
in liberalism.