In early February, after President Trump's well-received State of the Union address and Davos trip, economic adviser Gary Cohn was having lunch with the president and Chief of Staff John Kelly, in the small dining room off the Oval Office.

• For a year, Cohn had felt like he was beating his head against a brick wall, leading Groundhog Day tutorials on the benefits of free trade and the danger of tariffs.
• After helping steer Trump's victory on tax cuts, Cohn wanted another big assignment, commensurate with the skills, experience and appetite of a former president of Goldman Sachs.
• Advocating for Trump's infrastructure plan, which is dead on the Hill, wasn't juicy enough.
• Cohn said that if Trump could put him in a role where he would use 80% or 90% of his brain capacity, he'd stay. Otherwise, he should go.

Then Trump announced this week that he planned to impose sweeping tariffs on steel and aluminum — an embarrassment to Cohn, who had boasted to his Wall Street and Hamptons buddies that he had kept the president on the right track on trade.

• Cohn had planned to leave last week, according to the sources. But then with the departure announcements by Hope Hicks and Josh Raffel, Cohn didn't want to pile on, the sources said.
• Yesterday — with the details of the tariffs plan up in the air, but with Cohn convinced Trump was going big — he told POTUS that he'd leave in coming weeks.
• Trump would be willing to entertain calling Cohn back for a big job (White House chief of staff?), and Cohn would consider it, the sources said.

Why it matters: The Trump White House is bleeding talent, losing a half dozen or more officials who helped advise and contain the president. Worse, warn several officials, there is little to no succession planning to quickly fill vacancies with top-flight talent.

• This leaves the Trump White House understaffed and devoid of the moderating forces that helped shape his first 14 months in office. What remains is a more pliant, nationalistic staff, one much more aligned with Trump on trade, immigration and other issues.
• One source close to the White House told us: "POTUS rightly pointed out from the podium [yesterday] that he likes competition inside. They fight it out, he makes a decision. ... What happens when the dissent is gone?"

Be smart: So increasingly, the restraints are off. In this midterm year, and looking ahead to the reelection race, look for Trump to be more Trump — more Trump, The Nationalist.

• Hardliner Stephen Miller's influence may grow, on immigration and other issues.
• And now there'll be one fewer Dem telling Trump to cool it on the culture wars.
• Jonathan Swan emails me: "There’s going to be a power vacuum in the West Wing. People will fill it — and they’re much more likely to be people who agree with Trump on trade and immigration than a person, like Cohn, who opposes him and is willing to tell the president to his face that he’s wrong."