What CNN did to Bernie Sanders in the Iowa Democratic presidential debate — stabbing him with the gender card on behalf of a weakened Elizabeth Warren — was cheap and unfair.

And it was shameful.

I’m probably the last guy to defend Sanders. He is a man of the far left and I most certainly am not.

But even a conservative like me can see that Sanders was cheated out of the Democratic presidential nomination the last time, with the Democratic National Committee rigging the whole thing for Hillary Clinton. And now it’s happening again.

No wonder the Sanders supporters are angry.

What happened on CNN in Iowa was bad for journalism. But it sure was good for Elizabeth Warren and Joe Biden.

Sanders, the authentic candidate on the left in this cycle, as he was in the last, was surging in the Iowa polls. Warren, also on the left, was fading, desperate and in full panic. She began waving her gender card on that dangerous Intersectionality Highway where Democrats, addicted to identity politics, often crack up.

Just before the debate, CNN ran a story portraying Sanders as misogynist who thinks a woman couldn’t be elected president. That’s ridiculous. He doesn’t believe that.

And at the CNN debate, moderator Abby Phillip took Warren’s gender card, fashioned it into a knife and stabbed Sanders just weeks before the Iowa caucuses.

“Sen. Sanders, CNN reported yesterday, and Sen. Warren confirmed in a statement, that in 2018 you told her that you did not believe that a woman could win the election. Why did you say that?” Phillip asked of Sanders.

“Well,” Sanders said, “as a matter of fact, I didn’t say it.

“I don’t want to waste a whole lot of time on this, because this is what Donald Trump and maybe some of the media want,” Sanders added. “Anybody knows me knows that it’s incomprehensible that I would think that a woman cannot be president of the United States.

“Go to YouTube today,” Sanders said. “There’s a video of me 30 years ago talking about how a woman could become president of the United States.”

Phillip asked it again. And again, Sanders denied he ever said it. Phillip turned to Warren.

“Sen. Warren, what did you think when Sen. Sanders told you a woman could not win the election?” Warren was asked.

Excuse me? Sanders just denied it. But Phillip didn’t ask if Warren if Sanders was telling the truth.

Instead, Phillip repeated the Warren camp accusation as fact.

And this is how votes are herded.

Warren said she disagreed with Sanders, adding sweetly, “Bernie is my friend and I am not here to try and fight with Bernie.”

What a phony. He’s your friend? Of course he is. Who doesn’t engineer the public stabbing of their friends?

Before Sanders was shivved, Democratic establishment candidate Biden looked lost and frail and unsure.

Biden was like some elderly Uncle Joe retiree in line at 4 p.m. for the early bird dinner with the free Jell-O.

But who remembers that after Warren pointedly refused to shake her “friend” Bernie’s hand? Biden wasn’t even touched by CNN’s debate moderators. His questions were wrapped in pillows.

You might think all this is a coincidence, but then, you might be a moron. And you’re not a moron. Trust me.

And now, after weeks of stalling, House Speaker Nancy Pelosi has finally brought the impeachment of President Donald Trump to the Senate.

This means Democratic presidential candidates who are also senators, Amy Klobuchar of Minnesota, Warren of Massachusetts and Sanders of Vermont, are stuck in Washington as jurors.

And Joe? With Bernie on Trump jury duty in Washington, Biden is left to wander around Iowa with (former) Mayor Pete — who also was not challenged by CNN — and that radical billionaire environmentalist who made his gold in fossil fuels.

No wonder Sanders’ supporters are upset. They’ve seen this before. They watched the same game play out three years ago, when the Democratic nomination was almost his, and establishment media handmaidens of the Democratic National Committee protected Hillary Clinton, who lost to Trump.

A Sanders vs. Trump campaign in 2016 would have been a clash of populist titans. Sanders could have won. We might see this matchup in 2020. Establishment Democrats are panicked, and conventional wisdom suggests Trump would smash him, but I’m not so sure.

The electorate has been primed by relentless media attacks on Trump, who attacks them back. Americans are unsettled and worried about their future in a world undergoing economic upheaval. Bernie could win.

The Democratic base is energized for 2020. Sanders, who suffered a heart attack weeks ago, looks positively vital when compared to Biden. Conventional wisdom also once said Republican Jeb Bush couldn’t be beat. How did that turn out?

Joe is the new Jeb.

I suppose it would be much easier to focus instead on the Trump impeachment theater in Washington. But the script has been written, the Senate won’t convict Trump. It’s all posture and gesture and fundraising.

I disagree with Sanders’ policies, but at least he’s honest about what he wants to do. Establishment Democrats see Sanders’ base as full of energy and know they must stop him in Iowa and New Hampshire.

They feed Warren so Sanders doesn’t defeat Biden. And they’ll use friendly media to shape a stiletto and slip it between Bernie’s ribs.

Sanders’ voters have seen this one before.

John Kass is a columnist for the Chicago Tribune. His email address is jskass@chicagotribune.com