WASHINGTON (AP) — A Democratic senator from New Jersey is questioning whether Secretary of State Mike Pompeo’s trips to Kansas violate federal election laws.

Sen. Robert Menendez sent a letter Tuesday to the independent U.S. Office of Special Counsel seeking a review of Pompeo’s four trips to Kansas this year. Pompeo’s came last week for events on workforce development with Ivanka Trump.

Fellow Republicans have speculated for months that Pompeo might run for the Senate in Kansas next year. Menendez is suggesting that Pompeo’s trips could violate a law against federal employees engaging in political activity on the job.

The State Department did not immediately respond to an email seeking comment. Pompeo said in a Fox News interview Monday that he will remain secretary of state as long as President Donald Trump wants.