Donald John Trump compiled his pre-presidential notoriety by telling people “You’re fired!”

He parlayed that reputation as a tough guy into a winning presidential campaign. So … how does this guy fire the secretary of state? How does he tell Rex Tillerson his services no longer were needed?

He tweets it. He lets Tillerson hear about it along with the rest of Planet Earth. Classy, yes? Courageous, eh? No and no.

What’s more, the timing of this departure could not possibly have come at a worse time. The president didn’t bother to tell Tillerson that he was going to accept an invitation to meet with North Korean dictator Kim Jong Un. Tillerson was visiting Africa when word came from Trump.

The master of chaos has shown one more time — with many more sure to follow — how he seeks to govern. He doesn’t know what the hell he is doing.

Tillerson’s departure comes just as the State Department needs to start laying the groundwork for this upcoming bilateral meeting with Trump and Kim. How in the world does Trump think the State Department is going to prepare adequately for a summit that might be designed to persuade the North Koreans to cease its nuclear weapons development program?

Hell, State has many deputy and under secretary positions yet to fill. Tillerson was operating as a one-man band at the State Department, with damn few key deputy positions filled with capable diplomats.

Trump, meanwhile, keeps yapping and yammering about how “great” he is doing as president. He keeps telling us about all the top-tier minds seeking employment in the Trump administration.

I don’t believe Tillerson was a good choice to be secretary of state. If the president had any pull among top Republicans with actual diplomatic experience, he could have selected someone more qualified for this job than Tillerson.

The two men didn’t get along.

There’s the infamous “moron” epithet that came from Tillerson, directed squarely at the president.

There’s much work to do to get the president ready for this summit. It’s a big deal, given the insults he and Kim Jong Un have traded for the past year-plus.

To think, moreover, that Trump actually expects us to believe he is in command of the situation. This president does not know what he is doing.