WASHINGTON (AP) — Secretary of State Mike Pompeo has a new deputy, assuring a degree of continuity at the helm of U.S. diplomacy should he resign for a potential Senate bid.

The Senate voted overwhelmingly 90-3 on Thursday to confirm Stephen Biegun to be deputy secretary of state amid ongoing speculation that Pompeo will step down to run for the Senate from his home state of Kansas next year. Only three Democratic senators, Kirsten Gillibrand of New York, Ed Markey of Massachusetts and Mazie Hirono of Hawaii, voted against the nomination.

Biegun’s confirmation fills a vacancy that had opened earlier this month when current deputy, John Sullivan, was confirmed to be the new ambassador to Russia. Biegun, a former Ford Motor Company executive who currently serves as the U.S. special representative for North Korea, is widely expected to fill the secretary of state job at least on an interim basis if Pompeo departs.

Concerns that Pompeo’s possible departure would leave the State Department temporarily in the hands of the third-ranking diplomat, career foreign service officer David Hale, were partly behind legislative intrigue over Biegun’s nomination. Hale had testified in the impeachment inquiry into President Donald Trump.

Iran hawks in Congress leveraged those concerns to drop a legislative hold on the Biegun nomination to win a key concession from the Trump administration that could help their bid to kill the 2015 nuclear deal with Tehran.

To secure Biegun’s confirmation, the State Department agreed to release a portion of an internal legal opinion that says the U.S. has the right to demand that all U.N. sanctions on Iran be reinstated, despite Trump pulling the U.S. out of the nuclear deal. Leading Iran hawk, Sen. Ted Cruz, R-Texas, then lifted a hold he had placed on Biegun.

That drama raised new questions about Pompeo’s intentions. A former congressman and Trump’s first CIA director, Pompeo has been weighing a Senate campaign in his home state for months, though officials say no final decision has been made.