President Donald Trump has told advisors that he believes economic advisor Gary Cohn will leave his White House job if Trump decides to go forward with tariffs on imported steel and aluminum, people familiar with the matter say.

Cohn has mounted a last-ditch effort, along with other administration officials and some Republican lawmakers, to head off steep tariffs that threaten to unleash a global trade war.

Cohn has been summoning executives from U.S. companies that depend on the metals to meet this week with Trump to try to blunt or halt the tariffs, according to those familiar with the meeting planning.

Trump said in a tweet Tuesday there may be more staff turnover, even as he denied his administration is chaotic.

Turnover has been a constant of Trump’s administration. In the most-recent case, Communications Director Hope Hicks announced that she will resign last week after she testified before the House Intelligence Committee. Hicks was the fourth person to hold that position since Trump took office in January 2017.

She follows several other top aides to depart this year, including former Staff Secretary Rob Porter, who left the White House following reports that two ex-wives accused him of domestic violence. Chief of Staff John Kelly also made the decision to strip more than 30 aides, including Trump’s son-in- law Jared Kushner, of top secret clearances.

Cohn has served as director of the National Economic Council since the beginning of the Trump administration. Previously, he served as president and chief operations officer for Goldman Sachs Group Inc. since 2006.

An investment banker by profession, Cohn has become one of the more influential voices in the Trump administration.

--With assistance from Terrence Dopp.