By Cokie Roberts and Steven V. Roberts

A White House document arguing for tighter immigration laws states that “immigrants who come here illegally and enter the workforce undermine job opportunities and reduce wages for American workers, as does the abuse of visa programs.”

The Wall Street Journal editorial page, hardly a bastion of bleeding-heart liberalism, comments acidly: “What alternative economy are they living in?” “The real labor problem is a shortage, as the jobless rate has hit 4.2 percent nationwide,” adds the Journal. “America’s tight visa caps are sending high-tech jobs to Canada and agricultural production to Mexico.”

The Trump White House is living in several “alternative” universes, and its approach to tax cuts is even more financially irresponsible than its assault on immigrants. Government officials have repeatedly stated that reduced tax rates would “pay for themselves” by generating extra economic growth. But that claim has no basis in fact.

“We searched high and low and found no economic experts who could point us to evidence of tax cuts fully paying for themselves,” reports CNN. The nonpartisan Committee for a Responsible Federal Budget accuses the administration of making a “false claim” and “relying on magic bullets and fairy dust to pay for tax cuts.”

Another false claim bedeviling the administration was made by economics adviser Gary Cohn: “The wealthy are not getting a tax cut under our plan.” Washington Post fact-checkers labeled it a “ridiculous statement” and “one of the biggest myths spread by Trump and his aides.” Wealthy taxpayers would benefit enormously from administration proposals to lower individual rates, while canceling both the alternative minimum tax and the estate tax.

A New York Times analysis concludes that Trump and his heirs would enjoy a $1.1 billion windfall under his tax plan.

Fairy dust has infected the administration’s political thinking, as well. Since Republicans hold only 52 seats in the Senate, they have a very small margin for error, and yet the president keeps alienating GOP lawmakers with abusive taunts and threats of political retaliation. His latest target is Sen. Bob Corker of Tennessee, who he derided as “Liddle Bob” in a recent tweet.

Corker, however, is a key player on both foreign and fiscal policy, and Trump will need his support on a host of upcoming issues, from Iranian relations to spending blueprints.

“Under the normal, traditional rules of politics of the last 40 years of my life, a president would not poke a senator in the eye when he has a two-seat majority and a major legislative agenda needing to be accomplished,” former GOP Congressman Thomas M. Reynolds told The New York Times.

Trump and his team would argue that these are not “normal” or “traditional” times. And it’s certainly true that the president won the election by defying political rules and defeating more conventional candidates like Jeb Bush and Hillary Clinton. But running the country is a very different task than running for office. Passing legislation requires expanding alliances, not driving supporters away.

And while Trump has upended a lot of political assumptions, he has not repealed the principles of mathematics or majority rule. He attracted only 46.1 percent of the popular vote and trailed Clinton by almost 3 million ballots. His approval rating hovers at historic lows — 36 percent in the latest Gallup poll — but he keeps acting like a candidate, not a president, firing up his base of hard-core loyalists but failing to establish a broad coalition that can govern effectively.

“Donald Trump got elected with minority support from the American electorate, and most of his efforts thus far are focused on energizing and solidifying the 40 percent of Americans who were with him, primarily by attacking the 60 percent who were not,” Republican pollster Whit Ayres told the Washington Post. “That is great for his supporters, but it makes it very difficult to accomplish anything in a democracy.”

The Trump presidency is rooted in myth, not reality; fantasy, not facts. He’s an entertainer, not an executive; a magician, not a manager.

As Corker said in the Times, “When I watch his performances, you know, it very much feels to me like he thinks as president he’s on a reality television show. … It’s like he’s doing ‘The Apprentice’ or something. He’s just putting on an act.”

Corker’s right, with an ironic and dangerous twist: In this reality show, Trump is the apprentice, not the boss. He’s the amateur, not the pro. But he has a four-year contract and no one can fire him, despite his disastrous first season.

Steve and Cokie Roberts can be contacted by email at stevecokie@gmail.com.