The Wisconsin’s primary results were still fresh when Hillary Clinton and Bernie Sanders hit New York’s primary trail with fiery exchanges that lit up the race like a blast furnace. And here I thought the Republicans had all the fun with personal attacks.

Sanders led off with a mistaken (or invented) claim that Clinton had called Sanders “unqualified” to be president. Both Clinton and her campaign deny saying this, and a Google search confirmed that while Clinton may have inferred Sanders is not qualified, she did say so in quotes.

Legendary journalist Daniel Schorr, who covered politics for 70 years, once said reporters are “mischief makers.” I quite agree, from my own experiences. The mischief maker here may be The Washington Post, which ran a headline “Clinton questions whether Sanders is qualified to be president,” over a story where it never quoted Clinton uttering those words during a broadcast. On MSNBC’s “Morning Joe,” Clinton did point out Sanders’ difficulties in handling an interview with the New York Daily News, noting “he hadn’t done his homework.”

That was good enough for Sanders, who unloaded a fusillade, reciting judgments and votes during Clinton’s career that he said made her “unqualified to be president.” This was a harsh contrast with Sanders’ early campaign conduct, where he showed the world it was possible to run an effective, vote-getting campaign and remain a gentleman.

Sanders’ attack does surprise me. He had just won Wisconsin, after all, and not by a few points, but by landslide proportions, nearly 14 percent. Sanders didn’t allow the public and media to savor his win before distracting their attention with a full cannonade assault at Clinton’s inference, which would have sunk out of notice by lunchtime had Sanders not called attention to it.

Sanders advisers are reportedly telling him he’d be ahead in delegate count by now if he’d been harder on Clinton earlier in the campaign. There has been a noticeable shift in Sanders’ tone, one the The Boston Globe noticed in devoting a full column to it with the headline “A Dark Turn For the Sanders Campaign.”

It’s a dangerous gamble for Sanders, who alone out of more than 20 candidates running for president in 2016, has enjoyed consistently favorable ratings as a candidate in all polls. Yet Clinton does remain ahead in the delegate count even after her loss in Wisconsin.

The Democrats do not have any “winner take all” states. Their primaries award delegates proportionally to their votes, so Clinton picked up delegates in Wisconsin though her total against Sanders shrank slightly. It’s also a very odd strategy for Sanders — to make moves that could damage Clinton in the general election, when Sanders will ultimately need the votes of so-called superdelegates, who are charged with looking after the interests of the party.

Now to the Republicans.

They are behaving as usual, which is to say as bad boys. Donald Trump does not lose graciously, and Ted Cruz did not win Wisconsin good-naturedly, rubbing his win in a little.

It was to Trump’s advantage to take the focus off his disastrous Wisconsin loss and he did so quickly, reminding a New York crowd that Cruz had dissed New Yorkers to win the Iowa primary. That didn’t faze Cruz, who’s courting conservative Republican voters. He rejoined that yes, Trump was a liberal New Yorker.

Cruz is currently running a poor third in New York.

As far as Trump is concerned, while it is still mathematically possible for him to win enough delegates between now and the convention, he has to outperform, in almost every remaining primary, his best previous wins to do so. Wisconsin was only the latest in a series of serious setbacks for Trump, most of which, if not all, are of his own making:

— Trump made egregious mistakes in Wisconsin, attacking and mocking Republican Gov. Scott Walker, who has an 80 percent approval rating. His attack on Cruz’s wife, posting an unflattering picture of her on Twitter, was poorly received. And, of course, Trump saying women who seek abortions should be “punished” only reinforced a growing image of Trump as a man who likes women as trophies, but not as people.

— Trump’s campaign is in disarray. Politico reported on an astounding number of organization and morale troubles, all caused by Trump’s propensity to run things himself.

— Trump put together a delegate search and care team only last month. Having a team to track delegates is so fundamental for a presidential campaign that it should be one of the first sections set up.

I could go on. But however much he has conditioned the media, and the public, to expect “winning, winning, winning,” the reality is that Trump is losing, losing, losing in a number of crucial areas. Cruz and Kasich are wise to continue their fight.

Donna Brazile is a senior Democratic strategist, a political commentator and contributor to CNN and ABC News, and a contributing columnist to Ms. Magazine and O, the Oprah Magazine.