Senior White House adviser Stephen Miller waits to go on the air in the White House Briefing Room. (Joshua Roberts/Reuters)

Strange, isn’t it, that it was a lie that supposedly caused Michael Flynn to be fired? His false assurances to Vice President Pence about pre-election conversations with Russia were what evidently did him in as national security adviser.

If lies were always taken that seriously in the Trump administration, we might be living on the right side of the looking glass.

But they aren’t.

And we aren’t.

Consider, for example, the way the consistently truth-challenged President Trump applauded a top adviser last weekend after he went on national talk shows and told brash falsehoods.

(Bastien Inzaurralde/The Washington Post)

“Congratulations Stephen Miller — on representing me this morning on the various Sunday morning shows. Great job!” went the Trump tweet (bringing to mind the presidential praise after Hurricane Katrina to the hapless Federal Emergency Management Agency Director Michael Brown: “You’re doing a heckuva job, Brownie”).

What had Miller done to deserve the presidential attaboy? Well, among other things, the 31-year-old White House wunderkind had:

●Repeated, forcefully and with great conviction, evidence-free claims that there is widespread voter fraud in the United States. (Simply: There isn’t.)

●Insisted that the federal courts had no legitimate role in Trump’s executive order on immigration.

●Argued that there can be no questioning of the executive order from the judicial branch.

The Sunday hosts did their best to counter all this, but Miller was resolute. The Washington Post’s Fact Checker followed up, handing out Pinocchios like Kit Kats on Halloween.

[Fact Checker: Stephen Miller’s bushels of Pinocchios for false voter-fraud claims]

Then came Kellyanne Conway on Tuesday morning, less than half a day after she said Flynn had the president’s “full confidence.”

Now, being grilled by Matt Lauer on the “Today” show, she slipped and slid through important questions about just when Trump knew about Flynn’s pre-election conversations with the Russian government about lifting economic sanctions.

Viewers were left with no answers, except the increasing conviction that the Trump spokespeople are not to be believed.

Should proven liars continue to be given these platforms, especially on the Sunday-morning talk circuit? At what point are some administration officials no longer welcome in these influential national forums?

I asked John Dickerson, host of CBS’s “Face the Nation,” and George Stephanopoulos, host of ABC’s “This Week,” that question Monday. Both thoughtfully made the case that it’s important to have administration spokespeople on their shows, even if they don’t say much that’s useful or spout falsehoods.

“If they are representatives of the White House, then the bias should be for taking them on the air,” Dickerson said. The key is to provide context, he said — sometimes with a discussion immediately following, and, when appropriate, to do what he calls “adjudicating,” meaning pushing back, asserting established fact through repeated questioning, as he has often done.

Or sometimes, Dickerson says, viewers are best served by letting such guests speak freely, and then let “an informed and wise” viewership make its own judgments.

Stephanopoulos, who pushed Miller hard on the lack of evidence for his voting-fraud claims, told me that he was a worthwhile guest.

“Miller was elaborating on the president’s own assertion,” he said. “So it’s critical for us,” through questioning Miller as his surrogate, “to hold the president accountable.”

CNN, which declined Conway as a guest recently, in part for this very reason, is now being punished — if that’s the right word — with lack of access. Thus, CNN was the one network that managed to survive last Sunday morning without a Trump administration talking head. (Trump and his spokespeople also have continued to aggressively mischaracterize CNN’s solid reporting on a “dossier” that portrayed Trump as beholden to Russia.)

No doubt, having Miller on four other networks Sunday gave the administration a valuable platform for their talking points. It seems undeniable that some viewers came away believing his false claims.

What’s more, some sympathetic media were right there to take the material and twist at will: “George Stephanopoulos will NOT deny massive numbers of illegals registered to vote,” thundered a headline in PolitiStick, a right-wing website (one that promises it won’t annoy you with articles “unrelated to the culture war”).

It should all seem familiar. Remember: A couple of months ago, radio listeners were startled when a Trump surrogate offered the belief, on nationally syndicated radio, that “there is no such thing, anymore, as facts.”

Conway subsequently introduced, in an interview with NBC’s Chuck Todd, the mind-bending idea of “alternative facts.”

And then came Miller on Sunday. And Conway, again, on Tuesday.

So, no. There is no reason to be surprised about the public statements of the Prevarication Administration.

But there is reason to doubt whether giving proven liars a regular platform is something that ought to continue. Truth matters.

For more by Margaret Sullivan visit wapo.st/sullivan