HBO talk show host and comedian Bill Maher announced Thursday he would donate $1 million to Priorities USA, the Super PAC backing President Obama. Will other celebs join him?

Super PACs are the major campaign innovation of this election cycle. Through them, donors are giving unlimited amounts of money to help their favored candidates.

But so far, because the Republican candidates are in such an intense primary, nearly all of the millionaire donors have been giving to the GOP. The leading Democratic one, Priorities USA, had raised only about $4 million before Maher’s donation, compared to more than $30 million by Restore Our Future, which backs Mitt Romney.

WATCH MAHER DISCUSS HIS DONATION ON MSNBC’S ‘HARDBALL’:

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Obama campaign officials recently announced would explicitly support Priorities USA and encourage Democratic donors to give to it, even as President Obama has said he opposes the idea of Super PACs.

Now, the Obama campaign needs to find more people like Maher. The president is not lacking in rich supporters, from Bill Gates to Oprah Winfrey to LeBron James. But so far, most of them are sticking to giving $35,800, the maximum donation one can give to Obama’s various official campaign arms. (Obama for America and the Democratic National Committee)

For Obama’s Super PAC to match up with that of Romney or whoever eventually emerges as the GOP nominee, he will need donations in much, much larger amounts than $35,800. The next few months will test just how much some of the president’s supporters want to him to win re-election.

Follow Perry Bacon Jr. on Twitter at @perrybaconjr