1. The Pentagon is without a permanent leader.

President Trump pulled the nomination of the acting defense secretary, Patrick Shanahan, who resigned as a routine F.B.I. background investigation continued because of Mr. Shanahan’s divorce. His ex-wife had accused him of punching her.

Mr. Trump named Mark Esper, secretary of the Army, as acting secretary.

The change in personnel comes amid escalating U.S.-Iran tensions, which have left European leaders caught in the middle: They desperately want to preserve the nuclear deal with Iran that Mr. Trump rejected, but they are powerless to stop the U.S. sanctions that threaten it.