It should come as no surprise that President Trump is thinking about replacing Rex Tillerson as secretary of State—or that CIA director Mike Pompeo is the leading candidate. Tillerson's early exit has been talked about openly for months, Pompeo's rise as a likely successor for several weeks.
Trump and Tillerson are two very different men who never quite clicked.
Tillerson has spent much of his 10 months in office trying to polish the rough edges off Trump's blustery pronouncements about foreign policy—from threats of "fire and fury" toward North Korea to complaints about Britain and other NATO allies—only to watch helplessly as the president reverted instantly to form, rough edges and all.
A secretary of State is only effective if he or she can act as the president's chief foreign policy spokesman with full authority; otherwise, foreign governments won't waste their time listening. A single word from the White House can undo months of State Department work—as Trump did to Tillerson last spring, deriding the secretary of State's attempts to broker a truce between Saudi Arabia and Qatar.
Tillerson spent months trying to establish a close relationship with Trump, but it never quite happened—and once it was reported that he had described the president as a "moron," it was never going to happen.
Tillerson made other mistakes too. He made a complex, time-consuming reorganization of the State Department his principal mission; he would have served himself better if he had delegated that project to a deputy. He never quite mastered the arts of placating Congress and the media, essential parts of any Cabinet member's job description. Even worse, he made it clear that he considered it a waste of time to try.
His most likely successor, Pompeo, is different in all those ways. A former Republican congressman from Kansas, Pompeo comes across in public as a blunt-spoken partisan, closer to Trump in temperament. But in private he's quite knowledgeable about foreign policy, a product of his tenure on the House Intelligence Committee. As director of the CIA, Pompeo made a point of delivering the president his daily intelligence briefing in person almost every day—a canny way to establish a personal relationship with the boss. He'll be more careful than Tillerson to avoid creating the appearance of any distance from Trump. All that will likely make him a more effective secretary of State, in the sense that he will be more effective at pursuing the wishes of the president he serves—for good or ill.