WASHINGTON — Donald Trump’s killing of Qassem Suleimani brings America to the brink of a war with Iran without any congressional approval, in direct violation of the war-making authority Congress has under the Constitution.

Other presidents have started wars in reckless disregard of the Constitution, too, but Trump’s lawlessness is ubiquitous. It characterizes his entire presidency.

Consider Trump’s outing of the person who blew the whistle on his phone call to Ukrainian President Volodymyr Zelenskiy — tweeting a link to a Washington Examiner article headlined with the presumed whistleblower’s name, and then retweeting a supporter who named the presumed whistleblower.

Even before outing the whistleblower, Trump had whipped his followers into a lather by calling the whistleblower a “spy,” guilty of “treason.”

The outing not only imperils the whistleblower’s safety, it violates the purpose of the Whistleblower Protection Act, which is meant to protect people who alert authorities that government officials are violating the law.

It’s on this deeper level that Trump’s lawlessness is most corrosive. From now on, anyone aware of illegality on the part of a government official, including a president, will think twice before sounding the alarm.

Trump’s intrusion into the Navy’s prosecution of Chief Petty Officer Edward Gallagher on war crimes has the same corrosive effect.

Trump not only stopped the Navy from possibly giving Gallagher a less-than-honorable discharge, he upended the military code of justice, designed for the military to handle legal violations in its ranks, including war crimes.

Gallagher’s Navy SEAL accusers were themselves whistleblowers who broke the SEAL’s code of silence in order to stop a rogue chief. Now they face recrimination from within the ranks. From now on, any soldier who witnesses a superior officer committing possible war crimes will be more reluctant to report them.

Similarly, Trump’s ongoing intrusions into the Justice Department and the Federal Bureau of Investigation aren’t just efforts to derail investigations of his wrongdoing, they’re attacks on the system of justice itself.

Attorney General William Barr is supposed to be responsible to the American people but has become Trump’s advocate. Barr even advised the White House not to turn over the whistleblower complaint to Congress.

After misleading the public on the contents of special counsel Robert Mueller’s report, Barr bowed to Trump’s demand that the DOJ look into the origin of the FBI investigation that had led to the Mueller report.

And now, after the Justice Department’s own inspector general has found that the FBI had plenty of evidence to start its Russia probe — more than 100 contacts between members of the Trump campaign and Russian agents during the 2016 campaign — Barr refuses to be bound by the findings and has appointed a prosecutor to launch yet another inquiry into the origins of the Russia investigation.

The deeper systemic corrosion: From now on, attorneys general won’t be presumed to be administering impartial justice, and the findings of special counsels and inspectors general will have less finality and legitimacy.

Barr is part of Trump’s private goon squad, along with Rudi Giuliani, chief enabler Mick Mulvaney and Trump’s resident white supremacist, Stephen Miller.

Giuliani is using the authority of the presidency to mount a rogue foreign policy designed to keep Trump in power. It’s double lawlessness: Giuliani is bending the law and is accountable to no one.

Miller, meanwhile, is waging Trump’s ongoing war against people legally seeking asylum in the United States — featuring family separations, caged children and inhumane detention.

Miller even got Trump to pardon Joe Arpaio, the former Arizona sheriff who had been ordered by a federal judge to stop detaining people solely on suspicion of their immigration status. Arpaio disregarded the order, which is why he was convicted of criminal contempt of court for defying the order.

From now on, rogue sheriffs will be less constrained.

You see the pattern: Whistleblowers intimidated, the Justice Department politicized, findings of special counsels and inspectors general distorted or ignored, foreign policy made by a private citizen unaccountable to anybody, rogue military officers and rogue sheriffs pardoned.

Each instance is disturbing on its own. Viewed as a whole, Trump’s lawlessness is systematically corrupting the United States.

The real issue underlying Trump’s ordered assassination of Qassem Suleimani is not whether the Iranian general posed a danger to the United States. He almost certainly did. America faces many dangers.

The underlying issue is that Donald Trump cannot be trusted to lead America into war. Trump is unaccountable to America. He is lawless.

— — —

Robert Reich’s latest book is “The Common Good,” and his newest documentary is “Saving Capitalism.”