Give President Donald Trump credit for the no-holds-barred strategy he is employing in his ongoing war with the media.

Trump tweeted recently that the media are “the enemy of the American people.” He has now said “fake news” often enough that the phrase has become a part of the daily lexicon. Remarkably, Trump’s simple “denigrate the media” plan seems to have won some support. He has blurred the lines between truth and fiction and created an alternate universe in which news falls into just two categories: news that is favorable to the president and news that is fake.

In Trump’s World, the Pentagon Papers were fiction and Watergate was a ruse. How dangerously disturbing.

The Founding Fathers understood well that a free press — free to criticize, question and challenge government at every level, up to and including the president — is critical to the country’s long-term health. That’s why freedom of the press is among five freedoms guaranteed in the First Amendment.

Trump would be wise to heed the words of Republican Sen. John McCain.

“If you want to preserve democracy as we know it, you have to have a free — and many times adversarial — press,” McCain said. “And without it, I am afraid that we would lose so much of our individual liberties over time — that’s how dictators get started.”

McCain, of course, is right. The press has long been regarded as the Fourth Estate, the watchdog of the legislative, judicial and executive branches of government. Journalists at every level of media take, or should take, this watchdog role seriously. That means approaching every story with a healthy amount of skepticism, challenging convention and taking little at face value. That means writing and broadcasting stories that second-guess the president and his administration and that expose information the White House would prefer to keep private. No president — no matter the party — has ever escaped such scrutiny, which is exactly the way the framers of the Constitution wanted it to be.

Perhaps Trump, new as he is to politics, wasn’t prepared for the level of scrutiny he now faces. Given time, perhaps he will thicken his skin and quit crying fake news at every perceived slight.

The president and the media have serious roles in American democracy. Both serve the American people. Neither is the enemy.