"We're trying to put together a united ticket," Rangel told us this morning, attributing his endorsement to Cuomo's "money, poll numbers," but also "the Green attacks."

But is that the only reason he's supporting Cuomo? Green loyalists have suggested that it has a little something to do with 1199, and the potentially crucial support the union is providing to Democratic Congressional candidates.

Rangel also confirmed that 1199, which is one of Cuomo's biggest and most influential backers, is supporting New York's Congressional candidates and making contributions to the DCCC.

"I am confident that they are supporting our candidates for the congressional seats," said Rangel. "I've been talking with the Congressional campaigns and they are confident 1199 will be supportive."

But Rangel stressed that 1199's efforts to help Democratic candidates for congress was "separate and apart" from his decision to endorse Cuomo.

"I don't negotiate with 1199," he said.

--Jason Horowitz