Santorum Doubles January Fundraising as Romney Keeps Cash Lead

Republican presidential candidate Rick Santorum, who has emerged as the chief rival to Mitt Romney, more than doubled his fundraising after winning the Iowa caucuses last month.

Romney still raised more money than all of his Republican challengers and continued to receive the most financial support from Wall Street.

A former U.S. senator from Pennsylvania, Santorum raised $4.5 million in January after collecting $2.2 million in the entire last year, Federal Election Commission financial disclosure reports show. Romney brought in more than $6.5 million last month, according to his disclosure report.