Secretary of State Mike Pompeo has told three prominent Republicans in recent weeks that he plans to resign from the Trump Administration to run for the U.S. Senate from Kansas in next year’s elections. The problem: how to get out in one piece.

Pompeo’s plan had been to remain at the State Department until early spring next year, the three Republicans tell TIME, but recent developments, including the House impeachment inquiry, are hurting him politically and straining his relationship with Trump.

So Pompeo is rethinking his calendar, say the top Republicans, one who served in the Trump Administration, another who remains in government, and a third who served in several high-ranking posts and is active in GOP politics. The timing of Pompeo’s resignation now will be decided by his ability to navigate the smoothest possible exit from the administration, the three Republicans say.