Newt Gingrich is riding a wave of momentum following his convincing win in South Carolina, and now many are wondering if the tide has turned.
For the former House speaker, it was a smashing, across-the-board victory that has upended the race.
How did he do it?
First, debates. By trouncing Mitt Romney - and the moderators - he convinced South Carolina Republicans that he could win in November. Two-thirds said the debates were important. Most of them went for Gingrich.
More than half decided who to vote for in the last two days. Again, favoring Gingrich.
There was apparently little concern about his divorces. He won decisively among evangelical Christians and women.
Gingrich succeeded in portraying Romney as a "Massachusetts moderate," trouncing him among those calling themselves as very conservative.
Gingrich on Sunday stepped up his attacks on Romney as someone who just pretends to be conservative.
"You end up with a guy who is, I think, a very good salesman, very much wants to sell. But he has a really weak product," Gingrich said.
As for Romney, his support collapsed as he gave evasive answers about releasing his tax returns.
Romney announced he will release his 2010 tax return and an estimate of his 2011 tax return on Tuesday.