Mitt is now leading in New Hampshire. If he can hold NH and move up in Iowa. He’ll be the front runner, regardless of what national polls say.
Iowa is the key for Romney. Winning New Hampshire will no more make Romney the Republican frontrunner than Paul Tsongas' win in 1992 made him the Democrat frontrunner. Any Republican who runs close to Romney in New Hampshire will be the story like Clinton was in 1992 by finishing a close second to the regional favorite son.