OK, it wasn't a formal "endorsement", but the topic of the discussion was "Who would be the best campaigner/debater/candidate/winner"?
Actually, that question never made it to Newt. Cuomo answered it, but by the time the question got over to the other side, Russert re-phrased it and asked for a general assessment of the candidates. Newt said the only honest assessment at this point, based on the polls, was that the race was coming down to the two New Yorkers.
Hard to argue with him right now with Giuliani holding a 20 point edge over his closest competitor. But I think Newt realizes he has the potential to change the race dramatically. Cuomo certainly said as much.
I still don't know if he can win, but he has the ability to elevate the entire Republican field. He makes everyone a better candidate. And if the Democrats are on the other side acting like Democrats, they'll end up looking very small by comparison.