WASHINGTON — The Navy’s four-star fleet boss, Adm. Phil Davidson, has been nominated by Defense Secretary James Mattis to become the top military officer in the Pacific, a move that keeps U.S. Pacific Command under Navy leadership, according to a Defense Department announcement Tuesday.

Davidson’s top competition for the PACOM job, Air Force Gen. Terrence O’Shaughnessy, has been nominated to lead U.S. Northern Command, relieving Gen. Lori Robinson.

Currently the head of U.S. Fleet Forces Command, the 1982 Naval Academy graduate, will inherit a nuclear standoff with North Korea and a slow-motion conflict with China over its expansive claims of maritime rights in the South China Sea.

Adm. Harry Harris, the outgoing PACOM, developed a reputation for being aggressive with U.S. forces deployed in the region, which included a major show of force in November in which three aircraft carriers conducted a simultaneous patrol in the waters near the Korean peninsula.

Davidson has spent most of his career on the East Coast but spent recent months leading the Navy’s Comprehensive Review of readiness issues in the Japan-based U.S. 7th Fleet in the wake of last summer’s deadly collisions that killed 17 sailors.

Defense News reported in February that Davidson was likely to be the next PACOM commander.

Davidson has previously commanded the Eisenhower Carrier Strike Group, the cruiser Gettysburg and the frigate Taylor.

Prior to being Fleet Forces commander, he commanded U.S. 6th Fleet in Europe.

He gained experience earlier in his career at a staff job at PACFLT, according to his official biography.