Bear in mind that this comes from the same cable channel last seen making jokes about three-ways and Rick Santorum earlier in the evening, but that’s not the fault of CNBC’s John Harwood. Harwood told Rachel Maddow last night that the main funder of Newt Gingrich’s super-PAC, casino owner Sheldon Adelson, has written his last check for Gingrich in this race:

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Greg Sargent spoke with the head of the super-PAC, Rick Tyler, who acknowledged that he’s in for some rough days ahead:

The key question is whether the pro-Newt super PAC will be able to continue operating. The super PAC’s operations have been largely funded by billionaire casino magnate Sheldon Adelson, whose money has effectively kept Gingrich’s candidacy afloat.

John Harwood of the New York Times last night quoted a friend of Adelson saying that he had written his “last check.”

I just checked in with Rick Tyler, the head of the pro-Newt super PAC . Asked if he could continue operating without Adelson’s money, Tyler conceded: “Fundraising will be challenging.”

But Tyler vowed that the PAC would continue operating as best it could as long as Gingrich stayed in the race. Asked why Gingrich should continue after two losses that seem to render the cause hopeless, Tyler said the pro-Gingrich forces were betting on a contested convention, and would take it all the way to August.

The campaign itself probably can’t do much better at fundraising after the losses yesterday.  Conservative activists have been demanding consolidation behind Rick Santorum for several weeks, and their argument got a lot stronger after last night.  If Adelson cuts off the super-PAC, Gingrich won’t have many resources to run a competitive campaign.

The question will be whether Adelson himself acknowledges that.  He’s already been rumored to have pledged to support Romney if Gingrich didn’t win the nomination.  He might just decide to move his very large fundraising capability to Team Romney now and focus on defeating Santorum in the primaries.  That would make more sense than keeping Gingrich on life support at this point in the nomination process, especially since the primaries will be shifting away from states where social issues carry as much sway as they do in the Deep South, at least after Louisiana.  If Adelson really does decide to move onto the next phase, then Gingrich’s campaign will become moribund whether he suspends it or not.