(CNN) Former Pennsylvania Sen. Rick Santorum ended his presidential bid on Wednesday, throwing his support behind Florida Sen. Marco Rubio.
Satorum made the announcement Wednesday night on Fox News' "On the Record," saying he spoke with Rubio "for more than hour" Tuesday before making up his mind.
Santorum won the 2012 Iowa caucuses and ended that race with the second-most number of delegates to eventual GOP nominee Mitt Romney. But he was unable to capture any momentum this year despite extensive barnstorming efforts in Iowa.
He is the third Republican presidential candidate to drop out after Monday's caucuses. Mike Huckabee ended his campaign that night, and Rand Paul suspended his campaign Wednesday morning.
Santorum said that he and his family decided the best way to achieve his campaign's goals was to get out of the race.
"We decided that I think we could be better advocates for that in supporting someone who shared those values and is in a better position to do well in this race," Santorum told Greta Van Susteren, saying he was looking for a candidate that believed in helping struggling Americans, placed importance on traditional family units and who had the experience and understanding to take on ISIS.
"We decided that we wanted to find a candidate that really espoused the values that we believed in, someone who really focused their campaign on trying to help ... those who are struggling on the margins," Santorum said.
"That's why we decided to support Marco Rubio," he added.
When asked about a possible endorsement earlier Wednesday, Rubio said he hadn't spoken to the former Pennsylvania senator that day.
"I think he's fantastic," Rubio told CNN's Dana Bash.
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Santorum faced a drastically different landscape this year than he did in 2012. A crowded field of 17 Republicans and lackluster early polling kept him off the main debate stage for each of the GOP debates. He also faced competition for the hearts of evangelical voters, particularly from Texas Sen. Ted Cruz.
His retail politics were also no match for the media-centric, playbook-defying campaign of Donald Trump, the brash billionaire who left little room for candidates to win a moment in the spotlight.
Mike Huckabee drops out of 2016 presidential race
Still, Santorum's campaign was poised to learn from elements that overshadowed his bid in 2012, when the Pennsylvanian focused heavily on social issues. He made a pointed effort to not get dragged down by controversial comments he once made about homosexuality -- which included a comparison to bestiality -- that helped hamstring his earlier bid.
Without abandoning his socially conservative views, Santorum devoted more time to talking about his economic plans to revitalize American manufacturing and leaned heavily on his foreign policy knowledge to make the case he could best serve as president in an age of heightened global threats from terrorist groups like ISIS.
Santorum and Huckabee previously appeared with Trump at the billionaire's event for veterans that was held opposite the Fox News debate in Des Moines, Iowa, on Thursday.