Democratic presidential candidate Sen. Bernie Sanders told CNN's Brianna Keilar on Sunday that "of course" he would use tariffs as president, but only if used in a "rational way within the context of a broad, sensible trade policy" — unlike what he believes President Trump is doing in his trade war with China.

The exchange:

KEILAR: "You have made clear that China is treating the U.S. unfairly when it comes to trade. I understand that you don't agree with the president's tactics or his style. But if you were president, would you use tariffs to negotiate a deal with China?"

SANDERS: "That is one tool that you have. What the president is doing is totally irrational and destabilizing the entire world economy. You do not make trade policy by announcing today that you're going to raise tariffs by X percent and the next day by Y percent, by attacking the person you appointed as head of the Federal Reserve as an enemy of the American people, by denouncing the president of China, who last year you really loved as a great leader. This kind of instability and irrationality on the part of the president is causing very serious harm to the entire world economy.

KEILAR: "I understand your criticism of that. But you say this would be a tool. Is it a tool that you would use? Would you use tariffs?"

SANDERS: "Yeah, of course. If it is used in a rational way, within the context of a broad sensible trade policy, it is one tool that's available. You're looking at somebody, by the way, who helped lead the effort against permanent normal trade relations with China and NAFTA because trade policies that we have had in the past have lost us millions of good paying jobs and were written primarily by large corporations at the expense of workers and farmers. We need a rational trade policy today, not what Trump is doing by tweet."

The big picture: The populist Sanders has previously said that he does not believe in "unfettered free trade" and that he was "on the picket line in opposition to NAFTA" when it first came into effect.

Sanders' campaign told Axios last month that if elected, he would "begin a full review of tariffs against China, including advice from experts about which tariffs are working and what policies might better help American workers and change Chinese behavior. Tariffs may be 'part' of the answer, but the Trump administration lacks a serious strategy for managing China."

Go deeper: 2020 Democrats punt on Trump's China tariffs