Trump Threatens N.F.L. and Attacks Jemele Hill

Jalen Mills and Dexter McDougle of the Philadelphia Eagles kneeling before their game against the Arizona Cardinals on Sunday.WASHINGTON — President Trump threatened on Tuesday to use federal tax law to penalize the National Football League over players who kneel in protest during the national anthem as he sought to escalate a political fight that has resonated with his conservative base.

In one of a series of combative early morning tweets, Mr. Trump said that Congress should eliminate a law that has allowed the N.F.L. central office to avoid paying taxes as a nonprofit entity. “Why is the N.F.L. getting massive tax breaks while at the same time disrespecting our Anthem, Flag and Country?”…