By Eugene Robinson

WASHINGTON -- President Trump believes he is being persecuted, and that is a frighteningly dangerous mindset for a man with such vast power.

Amid a week of dizzying developments on multiple fronts, Trump gave a graduation speech Wednesday at the U.S. Coast Guard Academy portraying himself as a victim, unfairly besieged by those who would destroy him.

"No politician in history, and I say this with great surety, has been treated worse or more unfairly," Trump said. That is an absurd claim that cannot be taken seriously, of course, but it does give a sense of how the president feels about the scrutiny he faces.

Hours later, the Justice Department announced that former FBI Director Robert Mueller had been named as special counsel to investigate Russian meddling in the election and any possible collusion by persons connected with the Trump campaign. To my great surprise, the White House issued a statement that can only be described as calm, measured and appropriate.

"As I have stated many times, a thorough investigation will confirm what we already know -- there was no collusion between my campaign and any foreign entity," it said. "I look forward to this matter concluding quickly. In the meantime, I will never stop fighting for the people and the issues that matter most to the future of our country."

The tone of the White House reaction was widely praised on the cable news shows that Trump is said to watch obsessively. But the effect, if any, of such positive reinforcement was evanescent. It lasted only until Trump took to Twitter on Thursday morning.

"This is the single greatest witch hunt of a politician in American history!" he tweeted. A couple of hours later, he had more to get off his chest: "With all of the illegal acts that took place in the Clinton campaign & Obama Administration, there was never a special counsel appointed!"

So that's how Trump really took the news about Mueller's appointment: not well at all. The idea that he would be treated poorly, compared to the way other presidents were treated, seems to trigger an atavistic response. It is as if he went to a fancy restaurant and was shown to a table in a cramped corner, near the kitchen.

Now, with all of this weighing on him and gnawing at him, he leaves on his first foreign trip. The itinerary includes stops in the Middle East, the world's most explosive region. Having called during the campaign for an outright ban on Muslims entering the United States, Trump will give a speech that advisers have billed as an address to the Muslim world. He will visit Jerusalem, where geography equals theology and every false step has consequences. And by all accounts, the president gets cranky when he can't fly to one of his homes at night and sleep in one of his own beds. What could possibly go wrong?

The news this week has, indeed, felt like a barrage. On Monday, The Washington Post reported that Trump, during an Oval Office meeting with Russian Foreign Minister Sergey Lavrov and Russian Ambassador Sergey Kislyak, revealed highly classified information. On Tuesday, The New York Times reported that James Comey, whom Trump fired as FBI director last week, kept contemporaneous written accounts of his conversations with the president -- and that, in one of those encounters, Trump asked Comey to drop the investigation of Michael Flynn, who advised Trump during the campaign and whose Russia ties are being probed.

In two days, that was enough news for a month. But then on Wednesday came the Mueller appointment.

I share in the confidence expressed by Democrats and Republicans alike that Mueller will do a fair and thorough job -- and that FBI investigators, reportedly angry at the way Trump treated Comey, will look under every single rock. If there was collusion by the Trump campaign, I believe it will be found. But even if clear and convincing evidence of such wrongdoing exists, it will take time to unearth.

Meanwhile, Donald Trump remains president. He has access to the nation's most closely held secrets but cannot be trusted to safeguard them. He runs the White House like a family business, valuing loyalty over experience or expertise. He has no real grasp of policy, foreign or domestic. He feels himself under attack. Four months into his term, he brags to White House visitors about how he won the election. And there's not another one until 2020.

Eugene Robinson's email address is eugenerobinson@washpost.com.

(c) 2017, Washington Post Writers Group