Trump knew who he was hiring in his administration. Big players in the neoconservative movement that have been getting us into unnecessary war after unnecessary war. He knew they disagreed with his policy so why would he hire them as his key staff? He knew they would undermine him, it was inevitable.
What he did was give them enough rope to hang themselves.
By hiring them he took control of their destinies. They publicly went against the President of the United States that has a 97% approval rating in the GOP.
Trump was in control the whole time, all he had to do is let them show their narcissistic true colors and then he got rid of them one by one.
The end result is that these guys will never be influences in the GOP again, their career in the GOP is over. You would have to be insane to hire people like that again.
He completely wiped out the neoconservative warmongers in 4 years. The greatest accomplishment for our Republic in our lives.