Billionaire Carl Icahn shared his views in a wide-ranging interview Thursday with CNBC's Scott Wapner on topics such as government regulation, the economy, ETFs and his new Donald Trump administration advisory role on regulation.

But the most important thing may not be what the investor said explicitly, but what he implied about the market risk of a trade war with China under Trump.

"If you have a trade war with China, by definition, I remember the days something like that would really knock the hell out of the market, but maybe if you're going to do it, you should get it over with, right? So that's a consideration, you have to just make up your mind, if that's what you're going to do, you go do it," Icahn said.

Most telling is how Icahn ended the interview, unprompted.

"If you're asking me am I concerned about the market on the short term. Yeah I'm concerned about it," he said. "You can look at so many factors here that you have to worry about. Obviously, if you get into a trade war with China, sooner or later, I think we're going to have to come to grips with that, maybe it's better to do it sooner, but that's not my decision at all. I don't get involved with that."

To be sure, Icahn said he is not "involved" in the transition team's China trade policy discussions. However, the fact that he, as one of Trump's closest confidants, repeatedly brought up the stock market risk of a trade war with China during the 40-minute interview speaks to how an aggressive trade policy with the Asian country is likely being considered by the president-elect.

Icahn even emphasizes repeatedly that if the China trade war is coming, we might as well do it sooner and "get it over with," almost as if he's speaking to Trump directly.

If a trade war with China does happen, we can't say Icahn didn't warn us.

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