Roger Stone, Donald Trump’s former campaign adviser, sent a strong warning to the Republican party Friday. Should the Republican party continue to treat Trump “unfairly,” Trump will run as an Independent and it will kill the GOP.

“If he does [run as an Independent], you know what could happen? The Democrats would probably win, Trump would run a close second and the Republicans would run third. They can then go the way of the Whigs,” he said.

Stone claims that the power structure of the Republican party is afraid of Donald Trump because Trump’s wealth enables him to run without having to compromise.

“You can’t buy Trump. You can’t bully Trump,” Stone said. “And yes, the political class — the ruling class — they are apoplectic because they can’t get to Trump.”