WASHINGTON -- When Mike Pompeo became secretary of state on May 1, he advised his new colleagues at Foggy Bottom: "I want the State Department to get its swagger back." State doesn't really do "swagger," but career officials say morale has improved from the rock bottom level it reached with his predecessor, Rex Tillerson.

Pompeo, a boisterous ex-congressman, seems to be keeping his own swagger tendencies in check at State. His watchword so far has mostly been a version of "Keep your mouth shut." Many secretaries of state say they want to practice quiet diplomacy, and that was certainly Tillerson's goal. But Pompeo has made it an operating principle.

Pompeo is behaving at State much as he did as CIA director. His role is often that of a secret presidential envoy; he manages the North Korean denuclearization talks, the administration's most sensitive file, pretty much out of his briefcase. And, perhaps most important, he's able to speak authoritatively (mostly in private) for the president, something that Tillerson could never do.

The abrasive ideological edge that brought Pompeo to the House of Representatives as a "Tea Party" Republican in 2010 is still there; it surfaced visibly in his prickly answers at a Senate hearing last month. But at State, as at CIA, Pompeo has surprised some observers by championing career officers who were initially skeptical of him.

Discerning Pompeo's strategy is hard, because of his reticence, but you can see the outlines in his public comments.

Let's start with the State Department itself. Pompeo said from his first day that he wanted to bolster a demoralized foreign service, and he sought advice from a wide circle of former State officials, including some who had been very critical of Trump. Where Tillerson had left key positions unfilled, Pompeo has used his clout with the White House and Congress to clear appointments. More than a dozen major posts are likely to be confirmed next week, perhaps including four high-level "career ambassadors."

Pompeo's choice of David Hale as undersecretary for political affairs, traditionally the top foreign service job, is telling. Hale is a classic old-school diplomat. As ambassador to Lebanon and Pakistan, he deftly managed two of America's most sensitive accounts. His presence will encourage U.S. and foreign diplomats alike.

North Korea is Pompeo's hardest test. As CIA director, he was Trump's secret channel to Kim Jong Un; now he has the complex job of translating Trump's ebullient Singapore summitry into a verifiable denuclearization plan. To understand his approach, it's worth paying close attention to his brief remarks last week in Asia.

Pompeo signaled, notably, that he endorses Kim's desire for a gradual, phased process of denuclearization, linked with a broader de-escalation of tensions. He said in an Aug. 3 television interview in Singapore that "we are engaged in things that will improve the trust between our two countries" and that "the ultimate timeline for denuclearization will be set by Chairman Kim, at least in part."

Asked on Aug. 5 by a U.S. journalist whether, under a "phased approach," some reciprocal concessions "are possible before the end," Pompeo answered: "Yeah. That's right." Not exactly a roadmap, but that's Pompeo.

Even as Pompeo signals his readiness for a step-by-step process, he is insisting that U.N. sanctions "will remain in place until we have full denuclearization in North Korea," as he put it last week in Singapore. Pompeo's fear, presumably, is that premature removal of sanctions would allow North Korea to wiggle out of denuclearization, as it has in past negotiations.

South Korean officials have tried to reassure Pyongyang by promising a formal declaration ending the Korean War by the end of this year. This declaration might encourage reciprocal concessions from Kim, but it could also undermine the rationale for continued U.N. sanctions. Pompeo remains mum on whether he's willing to play this card.

Pompeo's other big headache is Iran. And despite President Trump's proclamation that he was ready for talks with Iranian leaders, Pompeo continues to voice a skeptical hard line. He told reporters on Aug. 5 that any progress in the relationship will "require enormous change on the part of the Iranian regime," but that "there's no evidence to date of their desire to change." Prepare for a long, slow squeeze.

Being chief diplomat for the most undiplomatic president in modern history can't be easy. The process broke Tillerson. But, so far, Pompeo has managed to reassure the State Department without enraging the man in the Oval Office. Maybe because he shares Trump's "big guy" persona, Pompeo has been the rare subordinate who stays close to the president, but not so close he gets burned.

(c) 2018, Washington Post Writers Group