Former Texas Rep. Ron Paul says a yearlong economic boom under President Trump is “a bit of an illusion” and that debt, inflation, and inequality could cause turmoil that benefits a “hardcore nucleus” of libertarians.

The libertarian Republican leader told the Washington Examiner that Trump could face a strong challenger in the 2020 GOP primary, especially if “things are really much worse."

“The big opening for us is the fact that this system is coming apart. We’re on the verge of something like what happened in ‘89 when the Soviet system just collapsed,” he said. “I’m just hoping our system comes apart as gracefully as the Soviet system.”

Paul doesn’t believe the U.S. will break into separate countries, but instead expects a rethink of monetary policy and an end to what he considers a U.S. “empire” overseas.

“We have ownership of these countries, but it’s not quite like the Soviets did,” he said. “I think our stature in the world and our empire will end, and that’s when, hopefully, the doors will be open and [people will] say, ‘Hey, maybe these libertarians have some answers to this.’”

Paul said “the country’s feeling a lot better, but it’s all on borrowed money” and that “the whole system’s an illusion” built on corporate, personal, and governmental debt. “It’s a bubble economy in many many different ways and it’s going to come unglued,” he said.

The former congressman for years has presented issues in stark terms, refreshingly so for supporters and with an alarmist edge in the eyes of detractors.

Also read: Republicans hopeful Trump has finally learned to legislate

Paul rose to prominence with 2008 and 2012 GOP presidential bids, running on an anti-war, pro-civil liberties message. When his son, Sen. Rand Paul, R-Ky., appeared well positioned for a 2016 presidential run, news outlets declared the country was experiencing a “libertarian moment.”

“The appearance of the libertarian movement has been set back partially because of Trump, but intellectually we’ve been doing well,” Paul said, describing a large "hardcore nucleus" of conference-attending enthusiasts.

Although broadly critical of Trump, Paul likes the president's talk about removing government regulations and implementing tax cuts.

“Trump’s being a good cheerleader. He’s a cheerleader for Wall Street, and I keep my fingers crossed, maybe lowering some of the taxes will help, certainly lowering the regulations. But I think the problems are so deep and structural,” he said.

Paul said he's disappointed with Trump's foreign policy, especially his approach toward North Korea and his support for Saudi Arabia's military role in Yemen.

“I think the foreign policy is a total disaster. Trump’s approach sounds good one day but the next day he’s antagonizing everyone in the world and thinks we should start a war here and there," he said.

Opinion: Trump's foreign policy: 'America First' and not value-neutral

Domestically, Paul views Attorney General Jeff Sessions as a threat to civil liberties and said he would be “delighted” if Trump fired him, though he’s not hopeful the replacement would be better.

The former congressman said he continues to view the U.S. as being on a path to fascism — on a long historical arch featuring authoritarian policies of Presidents Lincoln and Wilson.

“This time when we have a permanent war on terrorism there’s no backing off — and with the war on immigrants, and the borders,” he said. “Anybody who thinks we’re not doing too badly has not been flying on an airplane lately. That’s about as authoritarian-fascism as you can get.”

Paul said government policies that steer money to the wealthy create understandable anger among poorer Americans — pointing to the success of Sen. Bernie Sanders, the Vermont socialist, in his 2016 campaign for the Democratic nomination. Paul said a libertarian answer, halting inflation and "crony capitalism," would result in more freedom.

“We as libertarians have some work to do before [voters] are going to accept a true-blue libertarian,” he said, “but I think moving in that direction and having a popular candidate [in 2020] is very possible.”

"If they only hear our message, I know they would choose liberty and sound money and freedom and peace over the mess we have today," Paul said.

Also read: Congress heads into 2018 struggling with Obamacare