WASHINGTON -- While a dozen or more Republicans work to generate buzz about their 2016 presidential hopes, Rick Santorum is flying under the radar. And he might actually be the one who's best-positioned to draw support in early primary states.

After losing the GOP nomination to Mitt Romney in 2012, Santorum has been quietly building his operation for 2016. Instead of getting a gig on Fox News like fellow failed candidate Mike Huckabee, he runs a PAC called Patriot Voices. He heads to Iowa this weekend to join other 2016 hopefuls in Des Moines at a summit sponsored by Citizens United and Iowa Republican Rep. Steve King, who is often heavily courted in the lead up to the state’s caucus.

But unlike New Jersey Gov. Chris Christie and Texas Sen. Ted Cruz, Santorum isn’t heading into new territory. The former Pennsylvania senator is very familiar with Iowa. He’ll spend the next five days touring the state, speaking at county political events and trying to reconnect with the voters who backed him before.

One of the most forgotten victories of the 2012 Republican primary may be Santorum’s win in Iowa. That's partly because a vote-counting error led Romney to be declared the winner on caucus night. It was another week before Santorum was named the victor -- by 34 votes -- but by then it was too late to capitalize on the momentum boost that comes with winning the first electoral test, and Romney easily won the primary in New Hampshire. 

Santorum won 10 primary states in addition to Iowa. Had former House Speaker Newt Gingrich dropped out sooner, Santorum likely would have picked up South Carolina and Georgia. Overall, he tallied almost 4 million votes in the popular race. He was the last conservative left standing against Romney.

Santorum benefits from having run once before. He’s familiar with the process. He’s got high name recognition. And the criticisms of his social conservatism have already been levied, taking away some of the bite for his future opponents.

He’s spent the time since his last campaign raising money and supporting other conservative candidates. Last year, his PAC raised $3.2 million. Those are the kind of chits a candidate can cash in later. And he’s always had an appealing personal story. He has a book coming out next month that will focus not on politics but on his youngest daughter Bella, who has Edwards syndrome.

The GOP has a history of nominating the guy who came up short the previous time around: Romney, Sen. John McCain, George H.W. Bush and Ronald Reagan all failed on the first try. If history keeps repeating itself, that would make Santorum the frontrunner headed into the 2016.

The field is a lot different this time. There is likely to be more than one candidate vying for the moderate slot -- Jeb Bush, Romney and Christie could all run. And it’s already clear the conservative side will be crowded with folks like Cruz, Huckabee and Rand Paul.

One of the biggest initial tests they will all face is finding money to fuel a campaign. Santorum did secure a big-dollar donor in 2012, businessman Foster Friess. The wealthy oil investor could get Santorum’s operation up and running faster than many of his competitors'. Friess has already started fundraising for Santorum.

But Santorum has shown he can run an operation on a shoestring. He famously spent much of the year before the 2012 Iowa caucus crisscrossing the state in his pickup truck and meeting with voters. He won the old-fashioned way -- by working the ground -- and that's something that never goes out of style in Iowa.