Joe Biden leads in the major polls because people think he’s going to win, and people think he’s going to win because he’s leading in the major polls — but all it takes to puncture his Cloak of Inevitability is a shift in perceptions.

That shift looks like it’s taking place right now.

If anything could change the perceptions of Democratic primary voters, it would be weakness on the party’s sole sacrosanct issue: Abortion. Pro-life candidates and elected officials have all but been hounded from the party. The slow process began more than 30 years ago when Missouri Congressman Dick Gephardt, a pro-life politician for his entire career, felt it necessary to do a complete flip-flop in order to pursue his presidential hopes in 1988. Coincidentally, that was the same year Biden made his first stab at the Oval Office. Democrat primary voters didn’t go for Gebhardt’s schtick then, but what about Biden and the now?

Last Wednesday:

Biden’s campaign sought to clarify an answer he gave in May to a volunteer with the American Civil Liberties Union who asked him if he would support repealing the Hyde Amendment, a federal law barring federal funds for abortion services, except in the cases of rape, incest or when the mother’s life is in danger. Biden, who as a senator voted in favor of the amendment, told the activist, “It can’t stay.” His campaign, though, insisted he misheard the question, and that he does not support repealing the law — a position that put him at odds with his rivals, including Sanders, Sen. Elizabeth Warren and Sen. Kamala Harris.

But the next day, facing an outraged party, Biden backtracked on Hyde. “If I believe health care is a right, as I do, I can no longer support an amendment that makes that right dependent on someone’s ZIP code.” And this time he means it!

John Fund wrote on Sunday that “Democrats’ enthusiasm for their front-runner wanes as they worry about his gaffes and blunders.” While Biden has always been known — and kinda beloved — for his gaffes and blunders, this is different, “Now that Biden has caved to the left of his party on such a clear principle as federal funding of abortion, the pressure on him to keep going will ratchet up.” Former Obama strategist David Axelrod said Biden’s reverse course “raises questions about his own performance and his own steadiness and his campaign’s performance.”

Over at Salon, where Biden is usually seen as far too moderate, Bill Curry asks “Is Joe Biden the new Hillary?” Which, when you think about it, is probably the worst thing one progressive could possibly say about another, because Clinton committed the cardinal sin: She lost.

Not only that, but she lost to Trump.

Anyway, Curry plainly expresses the frustrations the party’s progressive wing has with the former veep:

With Barack Obama and Hillary Clinton in retirement, Biden is America’s foremost living proponent of bipartisanship. Why anyone still salutes it is a mystery. The reputation of every big bipartisan “achievement” of the last 30 years is in tatters: NAFTA; the mid-’90s crime and welfare bills; the late-’90s Wall Street deregulation; No Child Left Behind; the bankruptcy bill; the Iraq war. Biden was for every single one of them. Biden’s fans blame a generation of Democrats for these follies and say that it’s his bad luck to be the only one still around to blame. It isn’t true. A majority of Democrats in Congress voted no on NAFTA, the bankruptcy bill and the war. Only a handful of them voted wrong every time; only Biden shows up so often in critical roles (crime, bankruptcy, Iraq). It’s a unique record. Saying “everybody did it” just won’t wash.

Can a progressive Democrat cast a primary vote for Biden without becoming Literally Hitler? More and more, that’s the link of attack (I’m overly dramatizing here, but still) you’re seeing in the progressive press.

The quest to rid Biden of his Cloak of Inevitability is going so far now as to question the Iowa caucuses themselves. CNN Political Analyst Julian Zelizer wonders if Iowa “may have lost its magic.” He argues that “this new dynamic” of social media and cable outlets has allowed even a marginal candidate like Pete Buttigieg to “take his candidacy from relative obscurity to political significance.”

Complicating things further, pollster J. Ann Selzer writes that proposed new caucus rule “make polling even harder” in the Hawkeye State. She writes that once the new rules are in place, “virtual caucuses will be held in an effort to make the first-in-the-nation contest more accessible to those who might not be able to schedule several hours on a February Monday evening to take part in person.” It used to be that pollsters could form a pretty good idea of like caucus-goers, and poll accordingly. But once this new system is in place, that might no longer be true.

So Biden is polling well with today’s Democrats, but it’s unknown how well he might do with tomorrow’s. And that should be extra-worrisome for a candidate who never did well with yesterday’s Democrats, going all the way back to 1988. For an inevitable candidate with all the money and name recognition anyone could hope for, Biden looks more and more evitable each day.