Considering what the Trump administration's tax plan would do to the average American, Treasury Secretary Steve Mnuchin has a bizarre idea of what "fair" means.

The tax scheme being avidly pushed by Donald Trump, his Cabinet, and his cronies in Congress is as blatantly tipped in favor of the wealthy as it could possibly be.

The plan would raise taxes on nearly 69 million working Americans, while cutting taxes for top earners and giving billions away to their families — like the Trump kids — in the form of a repeal of the estate tax.

Trump has flat-out lied that the plan wouldn’t benefit him, which ABC’s George Stephanopoulos recently called out White House economic adviser Gary Cohn for lying about, forcing Cohn to admit to the administration’s mendacity.

And Sunday, Stephanopoulos laid into Treasury Secretary Steve Mnuchin, who has been spearheading the scheme, for his own attempts to twist the facts and mislead the American people about the plan, and specifically about how much someone like Trump would benefit from it.

Stephanopoulos repeatedly pressed Mnuchin about the White House’s transparently false talking points that the plan wouldn’t benefit the wealthy.

“It’s really hard to see how that can possibly be true, given the fact that your plan proposes cutting the top rate, eliminating the estate tax, eliminating the Alternative Minimum Tax, cutting that rate on pass-through entities,” he stated, noting that the non-partisan Tax Policy Center “calculates that 80 percent of the benefits will flow to the top one percent.”

Mnuchin’s response to the Tax Policy Center’s data? “That’s not a fact.” Okay, sure.

He then droned on about the ostensible aim of the plan being tax cuts for middle-income Americans, and every time Stephanopoulos brought up the data and details of the numbers, Mnuchin simply responded with basically, “Nuh-uh!”

When Stephanopoulos asked repeatedly if Trump would veto a final bill if it did in fact include income tax benefits for the wealthiest Americans, Mnuchin offered nothing but evasion.

“George, I can’t comment on what the president will do or what he won’t do,” Mnuchin sniveled.

And when pressed about the need to see Trump’s tax returns in order to offer any kind of support for the administration’s claim that he wouldn’t benefit from the plan, Mnuchin followed in his boss’s footsteps and got whiny about how “unfair” the question was.

STEPHANOPOULOS: How are Americans going to know whether or not the president gets this benefit if he doesn’t release his tax returns?

MNUCHIN: George, that’s just not fair! Because, again, we haven’t published the rules as to what’s going to apply to the pass-through rates, so you’re making certain assumptions that I don’t think are correct.

STEPHANOPOULOS: I wouldn’t need to make the assumptions if we had the president’s tax returns. And I guess that’s the question: The president himself has said publicly he’s not going to get a benefit from this tax plan. My question to you is: How are the American people going to know that if he’s not releasing his tax returns?

MNUCHIN: Again, George, I think the American public will be comfortable with the information they have. As you’ve pointed out, the pass-through rate is something we need to be careful about, as you’ve just described. And we’re going to make sure that there’s the proper rules — there’s going to be full transparency as we go through the legislative process, what those rules are, so that rich people can’t take advantage of it.

To argue that it’s “not fair” to say the public deserves actual proof, not merely the administration’s word, that Trump won’t benefit from this tax scheme is ridiculous. After all, it’s not like Trump is some kind of paragon of honesty. As the Washington Post noted in August, Trump’s litany of lies had already topped 1,000.

So Mnuchin will have to forgive the American people if we don’t just take their word for it that Trump, or any of them, is telling the truth now.

An administration mired in a full-blown scandal over financial abuse of power — in which Mnuchin himself is involved — and a massive humanitarian nightmare over their callous neglect of hurricane victims in Puerto Rico really has no business demanding the public just shut up and trust them on tax reform.

We already know the voters trust the media more than they trust Trump, and whining from a multimillionaire won’t do anything to change that.