WASHINGTON — While the country is mesmerized by Hurricane Harvey and North Korea heightens the threat of nuclear war, President Trump intensifies his war on our legislative and judicial branches.

The president already has his hands full picking fights with Senate Majority Leader Mitch McConnell and with a federal judge in Arizona by pardoning Maricopa County Sheriff Joe Arpaio. Now he is inviting a basic refresher course on the constitutional limits of the presidency and the co-equal powers of Congress and the judiciary.

Trump has already learned from Congress’ failure to repeal and replace Obamacare that he can’t simply will legislation into existence. As for the pardon of Arpaio — who was convicted on charges of criminal contempt for failing to follow the court’s instructions on racial profiling — Trump’s action has further inflamed the political hostility of Latino voters.

The president had already created a furor with his tin-ear contention that the protesters who clashed with white nationalists and neo-Nazis at a hate march in Charlottesville, Va., shared culpability for the street violence with those who organized the event.

After trying to clean up that political gaffe with a more conciliatory scripted speech, Trump turned around doubled down on his original “both sides” accusation in a 77-minute harangue at a bizarre political rally in Phoenix, reopening the controversy anew.

He also used the Phoenix rally to broaden his relentless war against the print and television reporters covering him, labeling them as perpetrators of “fake news.”

At the same time, Trump continued to traffic in the same sort of lies and misrepresentations masquerading as the truth that typified his 2016 election campaign and beginning of his presidency. During this period, most leaders of his Republican Party took cover, perhaps hoping Trump would somehow become restrained in his abusive rhetoric toward all political opponents.

But his marathon Phoenix outburst finally fueled open speculation from GOP establishment members like Mitt Romney and Sens. John McCain and Jeff Flake of Arizona about Trump’s mental stability.

The concomitant threat from North Korea, which this week test-fired an intercontinental ballistic missile over Japan, raised more concerns.

Trump’s penchant for impetuous decisions and short personal fuse has reminded many observers of the late President Richard Nixon’s musings that he could intimidate his North Vietnamese counterparts by giving them the impression he was a madman. Retired former CIA and DNI director James Clapper have openly expressed worry about Trump having his finger on the nuclear button.

When Trump fired his first chief of staff, the accommodating Reince Priebus, and replaced him with retired Marine Gen. John F. Kelly, the change was widely praised as a sign that Trump’s impulses would be reined in. But that optimism took a hit at the Phoenix rally.

Trump’s public support in most polls has dropped to little more than one-third of voters surveyed. Critics may now wish there were a simpler way to remove this contentious president than through the convoluted impeachment process, or through a cabinet revolt avowing his disability to serve.

Much therefore may depend on what Special Counsel Robert Mueller’s investigation into the Russian election meddling uncovers. Or further inquiries into the Trump family’s business deals could reveal major violations of the Constitution’s emoluments clause prohibiting gifts from foreign sources.

The next nail-biting test for this most unorthodox president is whether he will risk shutting down the government if Congress does not grant the necessary funding to build his promised wall on the border with Mexico.

It may seem incredible that Trump would go that far, recalling the fate of Newt Gingrich, who was deposed as speaker of the House after forcing a government in a dispute with President Bill Clinton in 1995.

But, then again, it also seemed incredible Trump would ever get to the Oval Office in the first place, and there he is.