Former Maryland Gov. Martin O'Malley is accepting public financing for his presidential campaign, making him the first major-party candidate to accept public financing since Republican John McCain in 2008.

To become eligible for matching funds, a candidate must raise at least $100,000 by collecting $5,000 in 20 different states. Now that the Federal Election Commission (FEC) has approved his use of public funding, the commission will ask the Treasury to make an initial payment of $100,000 to O'Malley's campaign. The presidential public funding program is financed through the $3 contribution taxpayers can make on their tax returns.

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The influx of cash, however, comes with tight spending restrictions. According to FEC rules, if the election were held this year, a candidate receiving public financing would only be allowed to spend $48 million in the primary. More specifically, the rules would restrict O'Malley from spending more than $1,829,200 in Iowa or $960,300 during the primary season if the election were this year.

O'Malley's decision to accept public financing was announced following reports that he may have to downsize his struggling campaign.

The former governor has been running a distant third in the race for the Democratic nomination, behind former Secretary of State Hillary Clinton and independent Vermont Sen. Bernie Sanders. A CBS News poll of Democrats and independents taken immediately after Saturday night's Democratic debate found that 7 percent believed O'Malley won the debate, and 14 percent thought it was a tie.

O'Malley had just $805,987 in the bank at the end of September, and has raised $3.3 million this year according to his latest filings with the Federal Election Commission.

Last month, O'Malley released a plan to overhaul the campaign finance rules, which includes a proposal for updated, more restrictive regulations and disclosure rules on political action committees and other outside groups.