My own experience shows what happens when things look grim: we look at the guy who isn't just smartest, but the guy who has "ideas". The one who has the big plan to get us out of a mess. We want the silver bullet that will change everything. We want, we demand, that our leaders come up with such a plan.
None of the people running have given out a real plan, a specific-enough-sounding plan, to make us go "Yes!" but one will come. When Herman Cain said "9-9-9" people went "Ooooh! Shiny baubles! This man has a plan!" Then of course, his plan was ripped to shreds for being ridiculous. But people supported him for a couple of weeks after that, simply because he had a weird plan! He had an idea!
Enter: Newt. The man known for having ideas. Known for throwing random stuff at a wall and seeing what sticks. It helps that he debates well and doesn't look lost under the bright lights. It helps that Evangelicals are willing to overlook a truly despicable personal character and a disturbing lust for power. He has been in Washington and out (sort of). Really, he isn't the absurd candidate he is taken for.
The one feather in his cap; the one he is saving; is one that would be really, really important in a general election against the seemingly pragmatic President Obama. He comes up with ideas. And people think nobody in Washington is doing that. As long as Newt has that secret weapon, there is nothing Romney can do to secure the nomination without a bloody battle to the end.