If I told you that a state legislature was trying to ram through an extreme partisan gerrymandering scheme at the very end of 2018, you’d probably assume I was talking about Republicans in North Carolina or Wisconsin. But I’m actually talking about Democrats in New Jersey, who are trying to amend the state constitution to practically guarantee themselves a permanent majority.

The scheme would require that state legislative districts be split evenly between districts that are more favorable to Democrats and districts more favorable to Republicans. The problem, though, is that “more favorable to Republicans” doesn’t mean “a district that elects Republican”; it means a district where Republicans get more votes than the statewide average in elections for governor, Senate, and president.

Because New Jersey is a heavily Democratic state, this standard allows the statehouse to create a number of districts that are majority Democratic and call them Republican-leaning. This definition, together with other procedural shenanigans explained by Slate’s Mark Joseph Stern, would allow New Jersey Democrats to draw a map where they would be practically guaranteed to win a supermajority in statehouse elections. Democrats typically win in New Jersey; this rule would change the outcome from a likelihood to a near inevitability.

Typically, constitutional amendments require a three-fifths vote in the statehouse — and Republicans have enough votes in the statehouse to block that. But Democrats are exploiting an obscure procedural rule that would allow them to get the vote through by conducting two simple majority votes. After the second vote, in January, the amendment would be put to a referendum for final approval.

This is dangerous. Research on democratic collapse suggests that when parties compete over who can rig the rules of the game, it can produce a race to the bottom: eventually, the fight escalates so far that one party seizes power outright. New Jersey Democrats are playing with fire.

The good news is that there’s already a backlash from inside the party. New Jersey Gov. Phil Murphy, a Democrat, has condemned the plan — as has former US Attorney General Eric Holder, who is currently leading the national Democratic Party’s project on redistricting. This opposition could, in theory, galvanize enough support to block the amendment at either the legislative or referendum level.

This kind of backlash against rigging the rules of elections is much rarer in the Republican Party, which has basically come to endorse anti-democratic practices on the national level. This is something Democrats can and should resist — there are a number of different tactics for doing so — without resorting to anti-democratic moves themselves.

So what’s happening in New Jersey is a test: Is the national Democratic Party’s commitment to democracy strong enough that it can stop a power grab from inside its own ranks?

Why New Jersey’s power grab is so dangerous

In their book How Democracies Die, Harvard political scientists Daniel Ziblatt and Steven Levitsky identify two core norms that keep democratic systems alive: Mutual toleration and forbearance. Mutual toleration is “the understanding that competing parties accept one another as legitimate rivals,” while forbearance is “the idea that politicians should exercise restraint in deploying their institutional prerogatives.” In essence, for democracies to work, parties have to accept that it’s okay if their opponents sometimes win elections and not try to rig the system to prevent that.

Republicans have become increasingly comfortable violating these norms, rhetorically painting Democrats as existential threats to the nation and changing a variety of electoral rules to suppress the Democratic vote and even disenfranchise Democratic constituencies altogether.

Democrats have been relatively unwilling to engage in kind. Among blue states, only Maryland has engaged in the kind of extreme partisan gerrymandering you see in several states where Republicans control the government. Democrats don’t try to suppress Republican voters as Republicans do with Democrats through voter ID laws, or attempt to strip elected Republicans of power before they take office, as the GOP has done to Democrats in North Carolina and Wisconsin.

And Democrats’ restraint is, according to Levitsky and Ziblatt’s analysis, crucial to the health of American democracy. Their research finds the most dangerous scenario is when both parties become willing to engage in win-at-all-costs tactics. The result is tit-for-tat escalation, where an anti-democratic move by one side is met with anti-democratic escalation by the other, a dangerous cycle that has culminated in one side seizing authoritarian control outright.

The 1970s conflict between Chilean socialist Salvador Allende and his opponents, where a series of increasingly aggressive power grabs by both sides ended in a military coup against Allende, is a clear example.

“Politics without guardrails killed Chilean democracy,” Levitsky and Ziblatt write. “Unable to permanently defeat each other and unwilling to compromise, Chilean parties threw their democracy into a death spiral.”

This is much more extreme than what has happened in the United States. But that doesn’t make the New Jersey move harmless. Power grabs don’t end partisan conflict — they egg on the other side to be more aggressive. When you’re dealing with a Republican Party that’s already abandoned key parts of its commitment to democratic norms, it’s not clear what this kind of escalation could yield in the long run.

New Jersey’s Democrats aren’t just trying to ram through an indefensible power grab: They’re encouraging the further decay of American democracy itself.

Can Democrats be the responsible party?

There’s a live debate over just how Democrats should respond to Republican anti-democratic moves.

It’s a hard situation to deal with. When one party is brazenly violating democratic norms, it can feel like a double standard to tell the other from responding in kind: a kind of unilateral surrender in the face of partisan hardball. But that’s not true. There are ways to fight back that neither violate basic democratic norms nor raise the risks of tit-for-tat escalation.

Some argue that Democrats should focus on defending the system, rolling back things like voter ID laws when they win state legislatures and challenging gerrymandered districts in the courts.

Others, like Roosevelt University political scientist David Faris, argue that Democrats need to go on the offensive with moves that would make voting and elections both more democratic and more favorable to Democrats. Proposals here range from statehood for DC and Puerto Rico to packing the Supreme Court with pro-voting rights justices to breaking up California into seven states to affect the Senate.

These tactics, both defensive and offensive, are pro-democratic in both the small-d and big-D senses. They expand the franchise or make undemocratic institutions like the Senate more representative while, at the same time, helping Democrats’ electoral chances.

But the New Jersey law does the latter at the expense of the former. It is anti-democratic in the small-d sense; it’s literally the same behavior national Democrats claim to decry in Republicans. If Democrats want to be defenders of democracy above partisan interest, then their responses to Republican anti-democratic moves need to be defensible on majoritarian grounds. The New Jersey gerrymandering scheme clearly isn’t.

This is why the opposition from Holder and Murphy is so encouraging. It shows that the party still has a commitment to mutual toleration and forbearance, a sense that certain actions really should remain out of bounds.

But clearly, it’s not yet enough. As of Thursday, when the statehouse held hearings on the plan, New Jersey Democrats were still barreling ahead. As the first vote approaches, national party leaders, like former President Barack Obama and likely incoming House Speaker Nancy Pelosi, should reaffirm the party’s commitment to fundamental democratic principles. National party leaders have powerful influence over the rank and file, and could do a lot to delegitimize the New Jersey plan and hurt its chances at the ballot box if it passes the state legislature.

National Republican leaders failed to do this — and as a result, they are complicit in a crisis of American democracy, where their party has become a threat to the system itself.

If Democrats don’t act, they’ll face the same stain on their record.