Updated: At Friday night's debate in Flint, Mich., Hillary Clinton joined with Bernie Sanders in calling for Michigan Gov. Rick Snyder's (R) resignation -- or be recalled. Below is something we wrote Feb. 9 about how it's not quite so simple.

And here is a tweet from Snyder early on debate night.

Until recently, the calls for Michigan Gov. Rick Snyder (R) to resign over the Flint water crisis have been relegated to grassroots protesters and political outsiders like Democratic presidential candidate Bernie Sanders.

But now it's going mainstream, thanks to a push by some Michigan Democrats and a recently approved effort to recall Snyder — albeit over an issue that has nothing to do with Flint. And it may soon start an all-out partisan war over the governor's future. If things get really bad, some are predicting Snyder might indeed resign rather than put the state through all of that.

Here's the latest in a fast-evolving story that could determine the governor of Michigan's future:

On Thursday, the head of Michigan's Democratic Party joined calls from some Flint residents for Snyder to resign, calling him "incompetent" and "morally bankrupt." His comments come after revelations that Snyder's administration knew about a potential connection of a deadly outbreak of Legionnaires Disease to the Flint water supply as far back as March. So far, at least 10 people have died, although the state has yet to prove there's a link between the two.

House Democratic Leader Tim Greimel has also said Snyder should resign conditionally — if he personally knew about the crisis and its connection to Legionnaire's Disease before he said he did.

Many other Democrats have stepped right up to the line but stop short of saying the "R" word, explaining they don't know all the facts yet about what Snyder knew and when.

But there are also important political reasons that could be keeping Democrats from calling for Snyder's head. If he goes, after all, Lt. Gov. Brian Calley (R) steps into the top job. And Calley is a top potential candidate for governor in 2018, which is when term limits dictate Snyder must step down. Generally, incumbency is a benefit in both warding off potential primary opponents and in winning the general election.

"There's no real advantage in a governor resigning," said Kelly Rossman-McKinney, the Democratic half of the bipartisan Michigan PR firm, Truscott Rossman. "You still have the same team in place. You just lost a key player."

Cautioned Steve Mitchell, a Michigan GOP lobbyist and pollster: "Now, you're running against a seated governor of the state."

It's a potentially fraught political situation for Democrats to wade through. But a recall petition moving quickly in the background of all this may force their hand sooner than they'd like.

On Monday, the state board approved one of 10 recall petitions for Snyder. The petition the bipartisan Board of State Canvassers unanimously approved wants to recall Snyder for putting an office that guides struggling schools under his control. At the time, the state Board of Education called the move “unconstitutional.”

State officials have rejected roughly a dozen recall petitions related to Flint, for reasons ranging to spelling errors to misinterpretation of the law.

But even as the issue is separate from Flint, there's little doubt this more innocuous recall petition will fast become a referendum on the governor's handling of the water crisis anyway. Voters, after all, can make their decisions based on whatever they want.

Rossman-McKinney thinks there are many people, on both sides of the aisle, who will be "clamoring to sign it."

"There's a lot of anger on both sides of the aisle in terms of how state government let down the people of Flint," she said.

And Michigan Democrats must soon decide whether to back it. Petitioners have a heavy lift — they must get almost 800,000 valid signatures in 60 days. (In 2012, Snyder signed a law shortening the window from 90 days, coming after threats of a recall petition about a lame-duck right-to-work bill that he fast-tracked.)

In other words, for this to succeed, Democrats need to help.

Looking ahead a bit, if the petition is successful, the question of whether Snyder should stay or go will ultimately be decided by the voters in August. That's an even bigger open-ended question.

A recent survey done by Mitchell's firm, Mitchell Research and Communications, suggests the decision would break down, perhaps unsurprisingly, along partisan and racial lines. Two-thirds of Republicans and one-half of white Michigan voters approve of the overall job Snyder is doing as governor. But just 18 percent of Democrats and 18 percent of black voters say the same.

A separate poll released in late January by Lansing, Mich., polling company EPIC-MRA shows 69 percent of Michigan voters don't approve of the way Snyder has handled the crisis, but just 29 percent think he should resign.

Recall efforts can backfire, too. A state over in Wisconsin, Gov. Scott Walker (R) survived a recall election in 2012 and arguably came out of it stronger than ever -- it was part of his presidential pitch.

In Michigan, political observers can't remember another recall effort of a governor, but Mitchell pointed out that recalls of state lawmakers have had lasting political implications. In 1983, a recall effort booted two Democratic state senators. They were replaced by Republican state lawmakers, turning the chamber red, where it's been ever since.

Rossman-McKinney thinks before it gets to that, Snyder would choose to resign rather than risk being a distraction for helping fix the problems in Flint. And having Democrats believe that he might do just that isn't a bad strategy either, given it could give Republicans a leg up in 2018 and make them less likely to back a recall.

But no matter what happens, the governor's fate is inexorably tied to Flint. And how it ends may rest in the hands of Michigan Democrats and what they decide to do next.