Rick Santorum Announces Presidential Run

Updated at 5:25 p.m. ET

Republican Rick Santorum, the former senator from Pennsylvania, announced Wednesday that he is running for president.

"Working families don't need another president tied to big government or big money," he said in Cabot, Pa.. "And today is the day we're going to begin to fight back."

Santorum, who appeals to his party's social conservatives, won the Iowa caucuses in 2012 and, donning his trademark sweater vest, challenged eventual GOP nominee Mitt Romney in several other states.

Santorum enters an already-crowded Republican field. According to Real Clear Politics' most-recent average of polls, he is in 10th place among his party's presidential hopefuls. Former Florida Gov. Jeb Bush has a slight lead over Wisconsin Gov. Scott Walker and Florida Sen. Marco Rubio, who are tied for second place. Most major polls show them all trailing Democratic front-runner Hillary Clinton.

For more on Santorum's candidacy, please read these stories on our It's All Politics blog:

Santorum Hopes To Catch Lightning In A Bottle A Second Time

5 Things You Should Know About Rick Santorum