Republican presidential candidate Donald Trump and the GOP establishment have always had a shaky relationship — and in the face of increased party tension, Republican power brokers may be pressuring Trump to quit.

As first reported by ABC News’ Jonathan Karl, Republican officials are planning for ” what would be unthinkable in a normal election year” — how to handle their party’s nominee dropping out of the race.

The report, from an anonymous GOP source, stated that senior party insiders are so upset and baffled by Trump’s erratic behavior that they are preparing a back-up plan for replacing him on the ballot before the November general election.

The fact that the plan is being crafted and was leaked to the press may indicate that the GOP is sending Trump an ultimatum — get your act together fast, or get out.

According to the ABC report, Trump would need to exit the race by early September in order for the Republicans to have enough time to replace him with another candidate on all 50 state ballots.

The news comes right as tensions between Trump and GOP leaders like House Speaker Paul Ryan and Arizona Sen. John McCain have reached a boiling point.

“This is absolutely unprecedented,” Karl said on “Good Morning America” Wednesday. “I am told that RNC chairman Reince Priebus is furious. He has had multiple discussions with Trump telling him he needs to drastically change course … They are so unable to control his message that they just don’t know and clearly think it is a possibility which is why they’re looking at these rules.”

But if his history is any guide, Trump isn’t going anywhere quietly… and certainly not without a fight. He earned his nomination and appears intent on seeing it through.

What do you think of the GOP’s back-up plan? Share your comment below.