Against Mattis wishes, Trump chooses new Joint Chiefs of Staff chairman

US President Donald Trump on Saturday announced he was nominating Army chief of staff General Mark Milley as his next top military advisor --
a new slap in the face for Pentagon chief Jim Mattis.

In choosing the 60-year-old Milley, a graduate of Princeton University known for his combat command experience,
Trump went against the wishes of Mattis, who reportedly favored Air Force General David Goldfein.

That choice (Air Force General David Goldfein) would have been in keeping with a tradition of rotating the post among the services.
There has not been an Air Force officer in the chairman's post since 2005.

The Pentagon's reaction to the announcement was somewhat frosty.

"We are aware of the president's nomination and share his confidence for General Mark Milley," Pentagon spokesman, Lieutenant Colonel Mike Andrews, said in a brief statement.

the Iran nuclear deal, which Trump withdrew from over Mattis' objections;
over the creation of a Space Force, which Mattis did not want;
and over the crisis at the US-Mexico border, and the deployment of troops there.