Watching Newt Gingrich’s graceful and low-key withdrawal from the presidential race Wednesday, it was hard not to think back to January, in Columbia, S.C., when he drew a wall-to-wall, fired-up crowd to celebrate his blowout victory in that state’s primary.

It was the most critical moment of the Republican race. In the days before South Carolina voters went to the polls, Republicans learned Mitt Romney had not won the Iowa caucuses after all; Romney’s narrow victory over Rick Santorum turned out to be a narrow defeat. Romney went on to win decisively in New Hampshire, but South Carolina turned into a disaster: a 12-point loss to Gingrich. As the race headed to Florida, Romney was one-for-three and Gingrich was gaining strength in the polls. Romney was in deep trouble.