Rick Santorum joins 2016 GOP presidential field

Cooper Allen | USA TODAY

Show Caption Hide Caption Rick Santorum’s 2016 presidential run: Why it matters USA TODAY's Washington Bureau Chief Susan Page explains the four reasons why Rick Santorum is worth watching for the Republican Presidential nomination in 2016.

Former senator Rick Santorum will once again seek the Republican presidential nomination, ABC News and the Associated Press reported Wednesday.

The former senator and House member was scheduled to announce his candidacy at an event in Butler County, Pa., near his boyhood home.

He joins a growing GOP field that is likely to include more than a dozen candidates.

Santorum, 57, mounted a surprisingly strong run in 2012 after languishing in polls for months leading up to the Iowa caucuses. He ultimately won in Iowa — belatedly, after Mitt Romney was initially declared the winner — and would go on to carry 10 additional states.

His base is social conservatives — he was the choice of 32% of Iowa caucusgoers in 2012 who identified as born-again or evangelical Christians. However, he'll face much more competition in 2016 for those voters.

Former Arkansas governor Mike Huckabee, who won in Iowa in 2008, is already in the race and also counts evangelicals and socially conservative members of the GOP as his core constituencies. He consistently rates higher than Santorum in polls. Other candidates figure to make inroads among groups who were key to Santorum's 2012 success, such as Texas Sen. Ted Cruz, who announced his bid in March at Liberty, the world's largest Christian university.

Santorum served two terms in the House before his election to a Pennsylvania Senate seat in 1994, when he won a close race against Democratic incumbent Harris Wofford. After winning re-election in 2000, Santorum lost badly to Democrat Bob Casey in 2006 in his bid for a third term.

Despite his 2012 run and primary wins, Santorum lags well behind in polls, including to GOP contenders who have never run a national race, such as Wisconsin Gov. Scott Walker and Florida Sen. Marco Rubio.

A further potential complication to Santorum's chances of breaking through in a crowded GOP field are rules likely to govern participation in debates. Fox News, which hosts the first GOP debate on Aug. 6, announced last week that it would restrict participation to candidates who place in the top 10 (including ties) of the average of the five most recent national polls ahead of the debate. Currently, Santorum registers around the cutoff mark for securing a spot.

Santorum slammed the criteria, National Journal reported. "The idea that a national poll has any relationship to the viability of a candidate — ask Rudy Giuliani that, ask Phil Gramm that," he said.

Santorum and his wife, Karen, have seven children. Their youngest child, Bella, was born with Trisomy 18, a genetic disorder that few children survive with past their 1st birthday. Bella recently turned 7. The Santorums, along with daughter Elizabeth, recently wrote a book about Bella titled Bella's Gift.

As in 2012, Santorum faces long odds, but he's quick to point out he's been there before.

"In January of 2012 I was at 4% in the national polls, and I won the Iowa caucuses," he said Thursday.

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