Hedge fund legend Leon Cooperman officially retired from the hedge fund business late last year, but he's still a welcome presence at CNBC's "Delivering Alpha" conference, where he sat for an interview with noontime anchor Scott Wapner.

During the interview, Cooperman shared his views on trade, interest rates and American politics, most notably how the Democratic Party's shift to the left has become one of the biggest threats to market stability that nobody seems to be talking about.

But the two began their conversation by asking Cooperman to share his thoughts on President Trump's trade policies. Cooperman said that the aggression toward China makes sense, but the US shouldn't be threatening Mexico and the EU. That will only succeed in further destabilizing the global economy.

"What we're doing with China, I understand, makes sense, but threatening Mexico, threatening Canada, threatening Europe makes no sense. This has created greater uncertainty in the business community, they don't know where to put the supply lines, they don't know where to build their plants, so they're cutting back on capex. And that's the weakness in the economy."

As far as interest rates are concerned, Cooperman said he doesn't understand central bankers (and President Trump's) rush to lower rates, particularly at a time when Cooperman believes governments should be more focused on fiscal stimulus.

"Europe is marching to the rules in Germany. With interest rates in Europe where they are, Germany should be spending a trillion dollars on infrastructure to rebuild, to help the economy grow."

It's already clear that negative interest rates don't work, Cooperman said. Japan showed us that. And it's not like the US economy is in such terrible shape. As Cooperman noted, home sales data in August saw the largest increase since June 2007.

With rates at 2%, "I can borrow all the money I want," Cooperman said. Money is already cheap enough (well, for consumers...the situation might be different for some banks seeking short-term financing. ).

"They're relying strictly on negative interest rates and negative interest rates have shown you in Japan they don't work, in Europe they don't work, and I don't think lower interest rates are what's necessary in the US. We had a nice housing number the other day...I can borrow all the money I want at 2%."

Finally, Cooperman and Wapner moved on to a discussion of the 2020 Democratic primary race. Equities haven't seen much of an impact from politics, Cooperman said, because right now, the market is assuming that President Trump will be reelected. But if Bernie Sanders or Elizabeth Warren start gaining credibility, things could turn around in a hurry. If Warren or Sanders happened to win, they would almost certainly usher in the next bear market.

"Right now, the market is assuming Donald Trump is reelected. If it looks like Elizabeth Warren or Bernie Sanders are credible opponents, the market will go down. They won't open the stock market if Elizabeth Warren is the next president."

Cooperman slammed Warren's policies, saying they were counter-productive and 'negative for capitalism'.

"Her policies are counter-productive, they're negative for capitalism...you don't make the poor people rich by making the rich people poor," Cooperman said.

As for Joe Biden, who somehow remains the front-runner despite a seemingly never-ending string of gaffes, Cooperman said he 'could live' with Biden's policies, but he's unsure of whether Biden would be acceptable to the party's more dominant progressive wing.

Watch a clip from the interview below: