It’s an open secret: New York governor Andrew Cuomo is on the shortest of short lists of likely 2020 presidential candidates.

He’s acting like it, too. The Empire State’s political favorite son has positioned himself as a leading anti-Trump voice, the tip of the Democratic spear. The president this week even publicly dared Cuomo to run in 2020, bleating: “Please do it. Please.”

But if Cuomo is angling to be the next Democratic nominee, why is he appearing to help Republicans in their effort to keep control of the House?

Cuomo’s little-publicized decision last year to accept the nomination of the obscure Independence Party is now shaping up, potentially, to be a disaster of national dimensions.

“It could decide two or three races,” says Dan Cantor, chair of the Working Families Party national committee. “And that could decide who controls the House.”

The reason: In accepting the nomination of the Independence Party, an obscure group run by ideologically eccentric radio and TV host Frank MacKay, Cuomo is ticketing with a slew of infamous Republican congressional candidates.

His ticket-mates include upstate reactionaries like John Faso and John Katko, both of whom Cuomo has personally sparred with in the past. Faso even once said Cuomo wasn’t “a man of principle and honor” like his father, former governor Mario Cuomo.

Cuomo doesn’t need the votes. He has a substantial lead in recent polls and is a virtual lock to be re-elected.

But his Independence Party cohorts aren’t all so lucky. Many are Republicans like Faso, currently engaged in tight races against Democrats in key swing districts. And being ticketed with Cuomo might net them slight but difference-making bumps this fall.

………

Still, it seems like counterintuitive politics. This bizarre situation is in play because the state of New York has an unusual electoral system, employing a thing called “fusion voting.” Used in only eight states, fusion voting is actually an interesting idea, America’s closest approximation to a proportional representation system.

The system allows one candidate to receive votes from multiple parties. New York’s is the most prominent and has some of the country’s highest-profile minor parties, with Nixon’s Working Families Party being the latest to break through.

This is the problem with folks like Cuomo, and Manchin, and Heitkamp:  They will throw over the party for the equivalent of a half-eaten cheeseburger.