ABC News' Michael Falcone reports:

Donald Trump is officially a man without a party.

The real estate mogul whose flirtation with the 2012 presidential race has never really ended despite announcing seven months ago he would not seek the Republican nomination has been signaling he wants to find other ways onto a presidential ticket.

Trump took another step in that direction on Thursday, switching his party affiliation from Republican to "unaffiliated," according to a source close to the reality television star.

According to the source, he did so because he is "disgusted" with the way Republicans are handling matters in Washington, including the recent payroll tax cut deal. But the move also sets Trump up for a potential third-party run for president - a possibility he began talking about almost as soon as he told his fans in May he wasn't running.

Trump has sought to reach out to the group, Americans Elect, an online, independent presidential nominating organization that has already made it on the ballot in several states, including California.

"Couple Donald Trump's name recognition with his extraordinary wealth and Americans Elect truly becomes a viable force in determining who the next president will be," Trump's top political adviser Michael Cohen told ABC News. "One thing is for certain, Donald Trump is adamant that Barack Obama must be defeated in 2012 under any circumstances."

This is not the first time Trump has changed his party registration. He registered as a Republican in the late 1980's, then switched to the Democratic Party in 2001 only to return to the GOP in 2009.

Trump hinted at an independent bid for president as recently as last week.

"Around the middle of May I'll be able to do whatever I want and I could run as an independent," Trump said in a web video he record. "If the Republicans pick the wrong person I would, in fact, seriously consider running."

Trump backed out as moderator of a proposed Newsmax presidential debate after most of the Republican candidates declined to attend citing a variety of reasons, including the Trump's own decision to keep the door open to jumping into the race next year.

"They want me to announce that I won't run as an independent candidate," Trump said, "but and I won't do that."

According to Americans Elect, more than 2.1 million people across the country have signed the group's petition in support of ballot access.

Should Trump win a spot on the Americans Elect ticket, "the merger would be something that both parties sould become concerned about," Cohen told ABC News.