Donald Trump. Mike Nudelman/Business Insider Real-estate developer Donald Trump would increasingly consider a third-party presidential campaign if the GOP establishment were to treat him unfairly, he told The Hill in a Wednesday interview.

"I'll have to see how I'm being treated by the Republicans," Trump said. "Absolutely, if they're not fair, that would be a factor."

The Republican businessman, who is leading most national polls, is under attack from many leaders in his own party who view his candidacy as a sideshow that could harm the GOP brand.

But as The New York Times previously reported, what some party higher-ups fear most is Trump launching a third-party campaign that could pull more votes from the Republican nominee than the Democrat in the general election.

"You've got to keep him in the tent," former Rep. Tom Davis (R-Virginia) told the newspaper. "He just wreaks havoc, and every vote he takes comes out of our hide."

A poll released earlier in this week may confirm that fear. Testing a hypothetical three-way matchup among Trump, former Gov. Jeb Bush of Florida (R), and Democratic front-runner Hillary Clinton, a Washington Post/ABC survey found Clinton (46%) easily ahead of Bush (30%) and Trump (20%).

Trump, speaking to The Hill about a potential third-party bid, singled out the Republican National Committee in particular for being unfair to him.

"The RNC has not been supportive," Trump said. "They were always supportive when I was a contributor. I was their fair-haired boy. The RNC has been, I think, very foolish."

The RNC criticized Trump last weekend after he panned the war record of Sen. John McCain (R-Arizona). Trump said McCain was "not a war hero" before reversing himself and repeatedly saying the opposite. McCain spent five years as a prisoner after his plane was shot down during the Vietnam War.

"There is no place in our party or our country for comments that disparage those who have served honorably," an RNC spokesman said in a statement.

Independent candidate Ross Perot, right, was seen as drawing votes away from George H.W. Bush, middle, clearing the way for Bill Clinton in the 1992 presidential election. AP/Doug Mills

The possibility of a third-party Trump campaign reminds some GOP leaders of Ross Perot, the Texas billionaire who ran independent White House bids in 1992 and 1996. Perot's first candidacy is often blamed for damaging President George H.W. Bush's reelection campaign and letting Bill Clinton win with a mere plurality of the vote.

"Perot's intensely nationalist and protectionist politics resonated with a lot of center-right voters that otherwise would have voted Republican," Dan Senor, an adviser on 2012 GOP nominee Mitt Romney's campaign, told The New York Times. "And the environment today is even more intensely populist. If Trump were to run as an independent, who knows what impact he could have in what will otherwise be a close election?"

Trump has also blamed Perot's candidacy for Clinton's 1992 win, and the real-estate developer previously seemed concerned that he could do the same for Hillary Clinton.

"I think every single vote that went to Ross Perot came from Bush," Trump told The Washington Examiner. "Virtually every one of his 19 percentage points came from the Republicans. If Ross Perot didn't run, you have never heard of Bill Clinton."