Tag new u s defense secretary james mattis r is greeted by marine general joseph dunford

I think there may be a small issue here!

James Mattis was indeed the 26th United States Secretary of Defense, serving from January 2017 to December 2018. However, he is not a "R" - his full name is James Norman Mattis.

And, Joseph Dunford is a Marine Corps general, but he is not a Marine general in the sense that he is not a general officer in the Marine Corps. He is a four-star general in the United States Marine Corps, and he served as the 19th Chairman of the Joint Chiefs of Staff from 2015 to 2019.

So, to correct the tag, it would be:

"New U.S. Defense Secretary James Norman Mattis is greeted by General Joseph Dunford, Chairman of the Joint Chiefs of Staff."