Coming off a last-place finish in Nevada, Rick Santorum was running the risk of being the latest also-ran in what appeared to be Mitt Romney's all-but-inevitable surge to the Republican presidential nomination.

Romney had just crushed main rival Newt Gingrich in Florida a few days earlier, following a blistering campaign that featured millions spent on negative ads and acrimony between the two top candidates.

Santorum left Florida early to be at his ill three-year-old daughter's bedside, but his campaign had already bailed on the media-heavy and expensive-to-win state to focus on Midwest contests. 

Now, Santorum, however fleetlingly, is the talk of the race again with three wins in one night, even though Tuesday's victories in Minnesota, Missouri and Colorado secure him a total of zero committed delegates at August's national convention in Tampa.

How'd "Rick Who?" climb back into the race? Well, showing up helps.

Santorum spent more time meeting voters in the states than any of the other candidates. It's the same thing he did in Iowa (successfully) and New Hampshire and South Carolina (really unsuccessfully).

In caucus states, pressing the flesh works, as the people a candidate meets and wins over in person are more likely to go in person and make their cases to others on Caucus Night.

Santorum, well-known as a social conservative who has opposed contraception and gay rights, has performed well in debates, but still lagged behind Romney and Gingrich in terms of name recognition.

He's relied on winning voters over one-by-one and convincing them he's the only conservative candidate who can take on Barack Obama on health care, the economy and what he insists is the Obama government's increasing attempts to take control of people's daily lives. (And also prove that he's not actually Jerry Seinfeld in a sweater-vest.)

Santorum's win in Colorado was Tuesday's big surprise, considering Romney won that state handily over John McCain in 2008.

Back then, Romney was viewed as more consistently conservative than McCain. But in this race, Romney's struggling to convince conservatives he's one of them. And while Gingrich stumbled as the conservative alternative, Santorum has been very effective in hammering Romney on the health-care plan he brought in as Massachusetts governor and urging Republicans not to cede the issue to the Democrats.

With key primaries looming in big states, Michigan and Arizona, where campaigns typically need to spend TV dollars, Santorum will need more than handshakes to convince voters he can win it all.

Otherwise, Romney could lock up the nomination as early as March's Super Tuesday. And Rick Who? could be another also-ran after all.