Secretary of Homeland Security Kirstjen Nielsen resigns

Department of Homeland Security Secretary Kirstjen Nielsen has resigned, President Trump tweeted Sunday. It's been a tortured relationship from the beginning, with Trump blaming Nielsen for every problem at the southern border and for the recent spike in families coming from Northern Triangle countries. Trump has long felt that Nielsen isn't "tough enough" when it comes to defending the border and kicking illegal immigrants out of the U.S., according to sources who've discussed the subject with the president.