CIA John Brennan normally avoids the political spotlight.
However, Brennan has recently become an outspoken critic of President Trump. Brennan often bashes on Trump’s decisions and character on social media. The president has recently responded to John Brennan with harsh criticism on Twitter.

Trump launched his scathing attack on former CIA Director in a series of tweets on Twitter. The president feels Brennan is a complete disgrace. This is not the first time he has castigated Mr. Brennan on social media. Brennan better look out.. The POTUS is not taking things lightly anymore. Things are becoming serious with President Trump and his team.
From subjectpolitics:
President Trump is a fighter with tremendous instincts and savvy who values advice but often chooses to keep his own counsel.
Earlier attempts to try to control President Trump failed miserably by GOP establishment figures.
America elected Trump because he took them all on and after getting rid of the people who advised him to be less than who he is, Trump has finally taken off the kid gloves and is getting tough with the swamp.
Look, the swamp has done everything to try to stop Trump because they have the most to lose if he succeeds.