California’s Gov. Gavin Newsom issued a warning to the Trump Administration after the Justice Department joined a Republican-led lawsuit on Thursday in an attempt to block the Golden State’s redrawing of congressional district lines. The Trump Administration is arguing that the new districts, which were approved by voters on Nov. 4, violate the Constitution.

In response to the legal action, Newsom’s press office said “these losers lost at the ballot box” and “soon they will also lose in court.”

On last week’s Election Day, California voters approved the Proposition 50 legislation to redraw California’s congressional districts, giving Democrats a stronger chance of taking five House seats from Republicans during next year’s midterm elections. The action was spearheaded by Newsom and other prominent California Democrats in response to similar recent redistricting efforts in Texas, which served to reshape several congressional districts to favor Republicans.

The battle of redistricting across the country has seen criticism from both Democrats and Republicans, with California Republicans suing in their state immediately after Prop. 50 was approved.

Now that the Justice Department has joined the lawsuit, here’s what to know about the latest legal tussle between the Trump Administration and the State of California.

What has the Trump Administration said in the lawsuit against California’s redistricting?

The DOJ describes Prop. 50 as “a rush-job rejiggering of California’s congressional district lines” in the lawsuit, arguing that “race cannot be used as a proxy to advance political interests, but that is precisely what the California General Assembly did with Proposition 50.”

Regarding race demographics, the DOJ says in a statement that it has “substantial evidence” to support its claim that ”the legislature created a new map in which Latino demographics and racial considerations predominated, in violation of the Equal Protection Clause,” which comes under the 14th Amendment.

“Race was a predominant factor in drawing at least District 13 in the Proposition 50 map,” the lawsuit claims.

“The race-based gerrymandered maps passed by the California legislature are unlawful and unconstitutional,” said First Assistant United States Attorney Bill Essayli of the Central District of California in a statement Thursday, adding that “California is free to draw congressional maps, but they may not be drawn based on race.”

In the lawsuit, DOJ attorneys say that Democrat lawmakers “sold a plan to promote the interests of Democrats in the upcoming midterm elections. But amongst themselves and on the debate floor, the focus was not partisanship, but race.”

The legal challenge also alleges that amongst Democrats, discussions were had about the Texas redraw, and that “Proposition 50 would serve as a “shield” against “racist maps,” to counter the Texas map. “The end result is a map that manipulates district lines in the name of bolstering the voting power of Hispanic Californians because of their race,” the lawsuit claims. 

TIME has reached out to the DOJ and Newsom’s press office for comment on the lawsuit. 

How has Newsom responded to the lawsuit and its claims?

Newsom’s press office has commented on what has been highlighted as an error in the lawsuit’s language, whereby the California’s State Assembly is referred to as a “General Assembly.”

“When Trump’s hand-picked hacks at DOJ can’t tell California from North Carolina, you know the lawsuit is about as credible as Trump’s ‘I don’t know Epstein’ line,” said Newsom’ press office, referencing the newly-released emails from the late convicted sex offender Jeffrey Epstein, which allege President Donald Trump knew of his conduct. Trump has long denied having had any knowledge of Epstein’s crimes.

“The Democrats are trying to bring up the Jeffrey Epstein Hoax again because they’ll do anything at all to deflect on how badly they’ve done on the Shutdown, and so many other subjects. Only a very bad, or stupid, Republican would fall into that trap,” said Trump on Truth Social, in response to the emails being released.

North Carolina, which has a General Assembly, passed approval for a new congressional map in late October, giving further advantage to Republicans in the state that was tightly contested. 

It is not yet known how Newsom or the State of California will officially respond to the DOJ lawsuit. 

The California Governor has previously won in court against Trump, notably in regard to the President’s deployment of the California National Guard earlier this year in response to immigration raid-related protests in Los Angeles. The deployment was made without the consent—or approval—of Newsom and other L.A. leaders.

A federal judge ruled in September that such deployment went against Federal law. In October, Newsom saw victory once again in court against the Trump Administration, after a federal judge blocked the President from sending any National Guard troops, including ones from California, to police Portland, Oregon.

Understanding the wider battle over redistricting

The redistricting rift between Democrats and Republicans was reawakened Texas announced plans to redraw its congressional districts in August. The move led Texas House Democrats to leave the state in an attempt to prevent the redraw’s approval.

But their efforts proved unsuccessful, as the new Texas congressional map was signed into law by Gov. Greg Abbott on Aug. 29. “This map ensures fairer representation in Congress. Texas will be more RED in Congress,” said Abbott. 

Newsom initially told Trump to “stand down” on the redistricting efforts in Texas, but as the Texas Republicans moved forward with their efforts, he started to make his own counter-action plans.

“Today is liberation day in the state of California,” said Newsom, announcing his own redistricting effort. “Donald Trump, you have poked the bear and we will punch back.”

(The mention of “Liberation Day” was widely seen to be a nod to Trump referring to his tariff announcement in April as “Liberation Day” for America.)

The measures in Texas have also been accused of being motivated by racial demographics. 

Democratic Rep. Vince Perez of the state’s 77th district said in August that, in his view, “Texas Republicans have used racial engineering to make sure Texans of color cannot meaningfully influence elections for Congress or the state legislature.”