For fifteen years, I was an enthusiastic, unapologetic Ann Coulter fan. I’ve expressed my share of disagreements with her, but on balance have supported and defended her many, many, many, many, many, many, many, many, many, times—from Left and Right alike—as one of the most fearless and principled assets to the conservative movement. Her books were defining influences on my own political development. She regularly raised devastating, critical points that more than a few conservatives were too meek to say or too conventional to notice. Meeting her in 2009 (above) was one of the biggest thrills of my political career, and I counted my autographed copy of Slander as one of my most prized possessions.

So when I say that Ann Coulter has officially lost me, know that I didn’t reach this conclusion lightly.

For the better part of 2015, Coulter’s aggressive support for Donald Trump has been a source of major consternation on the Right. Contrary to what some demagogic charlatans would have you believe, her underlying rationale is entirely correct: the next president’s level of conservatism on other issues will be irrelevant if he allows mass immigration and amnesty to give the Democrats enough new voters to guarantee them a permanent national majority. If this were, say, a two-man race between him and Marco Rubio, it would be perfectly reasonable to conclude that Trump is more likely to do the right thing on the issue.

Where Coulter’s conclusion breaks down is that Trump isn’t the candidate with the most credibility on fighting amnesty—Ted Cruz is. Conservatives don’t have to make a last-resort choice between an immigration hawk and a conservative; we can get both.

Considering that immigration is Ann’s own top issue, and her years of fighting for principled stands on every other conservative cause, one would think she’d be the last person to either run interference for an unreliable immigration voice or flippantly dismiss the importance of at least trying to get an actual conservative. Yet that’s exactly what she’s doing—and engaging in a shocking amount of dishonesty to do it.

We’ve already covered why Coulter is wrong about Ted Cruz’s eligibility for the presidency. I tried to be charitable toward her intentions in that post, but given how little respect she has for the goodwill of her readers, it’s worth going back to point out that not only is her reading of the law wrong, but crosses the line into malice twice: first her charges that her fellow conservatives who disagree do so because they’re “corrupt” and “interpret the Constitution to mean whatever we want it to mean” (no, conservatives said the same thing regarding Obama’s eligibility) and second her patently false claim that Cruz’s defenders haven’t cited “any Blackstone Commentaries […] any common law.” This is all beneath Ann…or it used to be.

Second, last week Coulter reposted a string of strong-sounding statements that Trump tweeted against the Gang of 8 bill in 2013, as a means of demonstrating Trump’s authenticity. Fair enough (if undermined by “Amnesty should be done only if the border is secure and illegal immigration has stopped” being among them). What wasn’t fair was the accompanying lie she told about Cruz (which she has since deleted from Twitter but remains on her Facebook page:

Meanwhile, advanced search of Senator Ted Cruz tweets for ANYTHING on immigration in 2013 turns up: “No Results.”

If that sounds more than a little implausible to you, it’s because that search doesn’t turn up zero results. It turns up 52 (and the same search on his campaign account turns up 70). Cruz did aggressively fight the Gang of 8 at the time, as Jeff Sessions and Steve King have vouched for, so to see Coulter try to rewrite history—and to do so in such a clumsy, easily-disprovable way—is astonishing.

But she wasn’t done. To hammer home that Cruz was allegedly AWOL on the Gang of 8, Coulter approvingly retweeted Mickey Kaus’s idiotic claim that when he should have been “stepping up” there, Cruz “staged [a] distracting, doomed O[bama]care stunt instead.” Funny, Ann didn’t think Cruz’s leadership on ObamaCare was such a bad thing at the time—she praised him for it in three separate columns, going so far as to call Cruz “majestic” in the third.

But the last straw is that she cannot content herself with a utilitarian good-faith case for Trump resting solely on immigration; she has to insult her readers’ intelligence by defending his authenticity as a conservative:

All the stories about Trump being a fraud keep turning out to be the real frauds […] The attacks on Trump from the “conservative” media calling him a socialist, a Democrat, a flip-flopper, a fake conservative are just name-calling. I notice that the accusers never include examples, not true ones, anyway.

Just name-calling? No true examples?

Trump’s history of donating to Democrats, identifying as a Democrat, claiming Democrats are better for the economy, condemnation of Republicans as “just too crazy right,” long pro-abortion past (and inconsistent pro-life present), advocacy of socialized medicine, weakness on protecting marriage and religious liberty, support for gun control, shameless embrace of eminent-domain abuse, current refusal to touch entitlements and support for campaign-finance reform, defense of a wealth tax, pro-amnesty sympathies, rabid opposition to Iraq, support for impeaching George W. Bush on leftist “Bush lied!” grounds (but opposition to impeaching Obama), endorsement of affirmative action, support for the auto and bank bailouts, doubling down on ethanol subsidies, defending Obama’s stimulus package, calling for executive pay caps, saying conservatives need to play nicer with the do-nothing GOP establishment, inconsistency on Syrian refugees, effusive praise of leftists such as Obama, Hillary Clinton, Nancy Pelosi, Bill de Blasio, and Maureen Dowd; and promising to be “the most politically correct person you’ve ever seen” after the election didn’t actually happen?

Seriously?

She is perfectly justified in criticizing Glenn Beck, Powerline, and others for attributing false quotes to Trump, but by focusing on those rather than the truckloads of objectionable things he really did say, she’s straw-manning just as dishonestly as the very media propagandists she used to expose. And it doesn’t get better from there—the rest of the column is basically Ann cherry-picking a handful of anecdotes that reflect well on Trump and pretending they suffice to refute the mountain of evidence against him, closing with the following:

Conservative pundits keep assuring clueless viewers that Trump is not a “real Republican.” They seem not to grasp that most viewers are saying, That’s fantastic! Thanks for reminding me. (I look forward to conservative talk show hosts 20 years hence billing themselves as “Trump Republicans.”)

Looking at what the party has become, I certainly hope he’s not a “real Republican.” I know he’s a real American. Those used to be the same thing.

The correct sentiment, applied disingenuously. “Real Republicans” are by and large worthless sellouts (which, ironically, is precisely why so many of them are flocking to Trump as someone they think they can work with to keep business as usual going). But Ann knows full well that conservatives don’t fault Trump for not being a real Republican; we fault him for not being a real conservative.

Political commentators aren’t just representatives of their own whims and narratives; they’re stewards of their readers’ trust. Readers take our word for it that we’re telling the truth, forgive our occasional missteps out of appreciation for our overall efforts, and—most applicable here—stick up for us against our detractors, risking the same slings and arrows and tying their reputations to our own. Narratives and smears against us reflect on them, too.

And most reflective are a writer’s real offenses. Coulter has forsaken her stewardship of her readers’ trust. Her flippant excuse-making for everything Trump says and pitiful fangirl swooning over his every movement have been embarrassing enough, but now she’s sunken beyond that and into outright lying on his behalf.

The worst part? Ann is undermining her credibility on all the things she’s correct about, which the Right desperately needs to hear. We need voices warning that getting immigration wrong would destroy conservatism. We need voices willing to say that Emperor Ryan has no clothes. We need voices to call out atrocious GOP blunders like Nikki Haley’s State of the Union response. We need voices willing to dissent from the Right’s conventional wisdom on presidential primaries.

Ann Coulter used to be that person. It’s why I admired her for so long, because such blends of independence, courage, and insight are rare enough, and deserve to be rewarded. But now she’s gone from writing about Slander to peddling it, from condemning mob mentality to joining it. No matter what happens in this election, destroying the credibility of one of conservatism’s finest may be one of the biggest tragedies of Donald Trump’s candidacy.