[Impy]

After Gingrich cut his own head off by attacking Romney from the left over Bain Capital and lost Florida, that’s when Santorum started winning (Iowa was his only win before that). Romney was far from the certain victor at that point but it was down to 4, Romney, Ron Paul, a hobbled Gingrich, and Santorum. He got my support by default.

[Will88]

It would take a good bit of work to nail down how well Santorum did in 2012 before it was decided, and how well Huckabee did in 2008 before it was decided. Santorum did win Alabama and Mississippi on March 14 and Romney reached the delegate threshold in late May. Here's an interesting look back:

With 100 percent of precincts reporting in Alabama, Santorum had 35 percent to Gingrich's 29 percent. Romney had 29 percent, trailing Gingrich by about 2,000 votes, and Ron Paul trailed with 5 percent.

In Mississippi, with 99 percent of the precincts reporting, Santorum had 33 percent to Gingrich's 31 percent. Romney had 30 percent, and Paul had 4 percent.

Very close, and a lots of vote splitting among conservatives between Santorum and Gingrich.

Santorum wins Alabama, Mississippi; Romney takes third in both states

Santorum suspended his campaign on April 10, 2012.

Santorum suspends campaign, clearing Romney's path