"Follow the science" is what progressive Democrats demand when the science suits them.

And yet, like Pavlov's salivating dog and the meat powder, a whiff of New York Gov. Andrew Cuomo prompts a predictable, conditioned response: a barking chorus of "whatabout whatabout" Ted Cruz or other Republicans.

There are plenty of Republicans to choose from, but as Cuomo began to publicly dissolve, it was Cruz, the conservative senator of Texas, who served up an awkward feast of himself. Cruz flew to sunny Cancun while his constituents were suffering and dying without power during a killer cold snap. He made it worse with a weasel trick, shifting the blame to his family for his jetting off to Mexico. His sin was about optics. And he deserves to pay for it.

But it wasn't Cruz who ordered senior citizens infected with COVID-19 back into nursing homes. Cuomo did that. It wasn't Cruz who allegedly manipulated the numbers of nursing home deaths, now under federal investigation, while writing a book about his admirable handling of the health pandemic. Cuomo did that.

Cuomo's decisions regarding COVID-19 patients allegedly harmed thousands of seniors. Letitia James, Democrat and New York attorney general, issued a report on the undercounting of deaths. The New York Post reported on an admission of a cover-up, and investigations began amid Democrat vs. Democrat bullying and shrieking.

But is this just a New York fight or does it suggest a larger truth about where American politics is heading?

The progressives aren't merely influencing Democratic politics. In the deep blue states, they've taken control as the old party apparatus crumbles. The violent summer protests were about flexing muscle. Liberal Democratic mayors cowered and were overwhelmed in New York, Chicago, Minneapolis, Los Angeles, Portland, Oregon and Seattle.

Progressive muscle now is about taking out Cuomo, which is critical to protect the ambitions of their real champion, Vice President Kamala Harris. Prior to Cuomo's meltdown, oddsmakers already were evaluating a Cuomo vs. Harris matchup in the 2024 presidential primary.

"Cuomo is in trouble," David Marcus, the New York correspondent for the conservative Federalist site and other publications, including the New York Post, explained on my podcast, "The Chicago Way."

"(Rep. Alexandria Ocasio-Cortez) of New York called for an investigation. Democrats called for impeachment, taking away Cuomo's powers. It's a mess. The media is trying to protect him, but that's hard to do."

What Cuomo allegedly did to the seniors sentenced to death in New York nursing homes is his doing, his fault and his sin. His alone. Make no mistake about this. He deserves what's coming.

And what is happening to Cuomo is what happened to Democratic mayors in big cities during those "mostly peaceful" protests: The old Democrats are being devoured by the progressives who've taken control of urban politics.

"The Democratic Party in big cities is no longer the big machine that it once was, yet Cuomo still operates as if he's a boss of Democratic machine politics," Marcus said on "The Chicago Way."

"But this is a post-machine political age."

Indeed. It is a truth learned firsthand by every liberal Democratic big-city mayor during the summer, as their downtown business districts were looted and burned. The mayors might be liberal, but they're no match for the energy of the progressives. And the landscape that nurtured the old Democratic bosses, like the Daleys in Chicago, like Cuomo's own father, Mario, in New York, has shifted.

"Progressive groups like the 'justice Democrats,' are doing an end run around the party machines that no longer have the patronage operations that they once did," Marcus said. "And Cuomo's learning that. He's not the boss in the party the way his dad was in the 1980s. The politics are different.'"

What's changed is that the old bulls lost control. The new Democratic patronage is found in the public workers unions, the public-school teachers and others. They flexed their muscle in the summer. Now they want to use it some more. And they'll use it to rid the political world of possible rivals to Harris.

Until he began to collapse, Cuomo had been propped up by much of the media, by CNN in particular, in those painful, cloying interviews with his brother Chris, and by other outlets.

The governor was even given an Emmy for his handling of COVID-19 news conferences, an anti-Trump mannequin. But that's over.

Joe Biden is president. Cuomo fights for his life. Harris waits for an opening. Once the meat powder was in the air, the rest was inevitable political biology, where only the strong survive.

And that's science too, isn't it?

John Kass is a columnist for the Tribune Content Agency.