FLINT, Michigan — In perhaps their most boisterous exchanges yet, Hillary Clinton and Bernie Sanders traded barbs on trade policy, corporate welfare, and gun control.

In fact, it seemed like the only thing they could agree on was who to blame for the crisis that brought them to town.

Even as they spoke Sunday evening, lead-poisoned water continues to flow here in Flint, months after it became a national news story. And the crisis over toxic drinking water threatens to make the Republican Party radioactive in Michigan for a generation.

The two leading Democratic presidential candidates took advantage, holding the debate here to turn the screws on the GOP, joining together for the first time to call on Michigan Gov. Rick Snyder to resign. Outside the debate venue, at the University of Michigan-Flint, dozens of progressive protesters marched against Snyder, holding signs with the governor depicted as a devil with red horns.

The catastrophe in Flint dominated the first quarter of the debate, with locals posing questions laced with skepticism to the two presidential candidates, asking what they could actually do to help end the hardship that had befallen them and thousands of other local families.

“It is beyond belief that children in Flint, Michigan, in the United States of America in the year 2016 are being poisoned… I believe the governor of this state should understand that his dereliction of duty was irresponsible. He should resign,” Sanders said, near the start of the debate, generating an enormous round of applause.

“The governor should resign or be recalled,” Clinton added, the first time she had called for this measure. “It is raining lead in Flint.”

It’s part of a broader effort by Democrats to put the blame for the town’s drinking-water crisis squarely on the GOP. The political fight over Flint’s water may be the single issue that pushes the state out of Republican presidential contention for good.

The increasing pressure is having an effect on Republicans who Democrats have blamed for various parts of the Flint debacle. Snyder, sensitive to the attacks that were coming his way during the Democratic debate, tried to dodge blame in real time:

Snyder’s job-approval numbers have dropped precipitously as a result of the drinking-water catastrophe: A statewide poll in January found that 69 percent thought he had handled the crisis poorly.

In Washington, Sens. Debbie Stabenow (D-MI) and Jim Inhofe (R-OK) have put together a bipartisan $250 million package for drinking-water infrastructure that would help Flint and communities like it. Stabenow blames a Republican senator for preventing its passage. Sen. Mike Lee (R-UT) is single-handedly holding up this aid package, but public pressure—led by Stabenow—is forcing him to find a way to back down gracefully.

The Flint water crisis is the latest development in a longer-term trend: For years, Michigan has been drifting out of the swing-state column and becoming much more solidly controlled by Democrats, due in part to changing demographic trends.

While downplaying the possibility of a “permanent realignment,” Saul Anuzis, the former chairman of the Michigan Republican Party, acknowledged the longer-term shifts are “a challenge” for the GOP.

“Demographic trends tends to be similar to national trends,” he told The Daily Beast. “More minorities, more immigrants, and we as a party have to work harder to get both.”

In the 1980s, Democratic pollster Stan Greenberg used Michigan’s Macomb County as a case study for so-called Reagan Democrats—moderate Democrats who were open to supporting a Republican for president. But this phenomenon has faded and Michigan has become increasingly dominated by Democrats in presidential years.

Despite perennial Republican hopes that Michigan could be the key to the White House, Democrats have won Michigan in every presidential election since 1992.

A new NBC News poll released Sunday also illustrates this point: Clinton would beat Republican Party frontrunner Donald Trump by 16 percentage points; while Sanders would beat Trump by 22 percentage points. By comparison, President Obama beat former Massachusetts Gov. Mitt Romney by less than 10 percentage points in 2012.

The Flint water crisis will affect this community for decades. Thousands of children will need to be monitored for long-term health consequences. The political effect it will have on the state could linger just as long.