This post, originally published in June, has been updated with the latest news.

Behind a significant number of GOP senators who oppose their party's health-care bill is a governor who also hates it.

Of the 13 GOP senators who have concerns about or don't support the new version of the legislation, eight of their state's governors also don't support it. That's several more governors voicing their opposition since we last checked in June.

An additional three of those governors conspicuously won't comment on it, or, in the case of Kentucky Gov. Matt Bevin (R), they begrudgingly support it. (It's “not a really good bill,” Bevin recently said.)

All but two of these governors are Republican or Republican-leaning. (Alaska Gov. Bill Walker is an independent who says he's “very concerned” about the bill.)

In other words, Republicans' health-care bill isn't popular with a significant number of Republicans who would have to vote for it, and isn't popular with a significant number of Republicans who would have to implement it.

How governors feel about this legislation can make or break whether the bill can pass.

Republican senators who are on the fence about Senate Republicans' health-care bill will have a hard time voting for it if their governor back home doesn't support it.

Sen. Dean Heller (R-Nev.), who has become a bellwether opposition figure, is a perfect example. He announced he opposed the first version of the legislation in a news conference alongside GOP Gov. Brian Sandoval, the most popular politician in the state and a huge proponent of keeping the Medicaid expansion.

“If you want my support (on repealing Obamacare) … you better make sure that the Republican governors that have expanded Medicaid sign off on it,” Heller said.

Colorado Gov. John Hickenlooper (D) traveled to D.C. in June and held a news conference to urge Sen. Cory Gardner (R-Colo.) to go from undecided to a “no” vote on the bill. “Trust me, by hook or by crook I will get a hold of him before there’s any vote,” Hickenlooper dramatically declared. “I’ll go camp out on his doorstep if I have to.”

(The New York Times reports that Gardner called Hickenlooper “literally 30 seconds” later. Gardner still hasn't taken a position on the new bill.)

Alongside Hickenlooper was Gov. John Kasich (R-Ohio), who has been one of the most outspoken — and quotable — Republicans opposed to this bill.

“They think that's great? That's good public policy?” Kasich said of the nonpartisan Congressional Budget Office estimate that the first version of the bill would lead to 22 million more people — the equivalent of the population of 16 states — uninsured over the next decade. “Are you kidding me?”

The same afternoon, Sen. Rob Portman, Ohio's only Republican senator, more or less agreed: “I continue to have real concerns about the Medicaid policies in this bill,” Portman said in a statement announcing his opposition, “especially those that impact drug treatment at a time when Ohio is facing an opioid epidemic.”

These Republican governors aren't suddenly pro-Obamacare. They're concerned getting rid of a health-care law that has insured some 20 million will cost their states money that, in many cases, they don't have. The definition of rolling back Obamacare is to unwind the federal government's contribution to people's health care. That leaves state government with two politically unpopular decisions. As I wrote in May after House Republicans passed their version:

States are probably going to be on the hook for billions of dollars of health-care costs, especially for the poor and sick. That means these governors will have some tough choices to make: Do you find a way to raise taxes/cut other services to keep your most vulnerable population insured? Or do you just stop insuring them?

Democrats hoping to pick up governor's mansions are hoping this Senate health-care bill becomes a campaign issue for GOP gubernatorial candidates as much as it's become a budget issue.

Democrats' governors association launched a tracker of where top GOP governor candidates are on the bill. It's also paying for a digital video ad in six states trying to pin down Republican governor hopefuls. At the top of the list is Republicans' nominee in Virginia's governor's race later this year, Ed Gillespie:

Image from Democratic Governors' Association's digital ad.

All that's to say: When it comes to debating health care, GOP governors are pinched financially. Some of them could be boxed in politically. And the more of them oppose their party's attempt to change Obamacare, the less likely Republicans will actually change Obamacare.