Here’s what Newsom is doing now.
California has opened a new front in the growing battle over mail-in voting, taking direct aim at the U.S. Postal Service just months before Americans head to the polls for the 2026 midterm elections.
The state is challenging new USPS rules governing mail ballots after the Supreme Court handed President Donald Trump a significant legal victory, allowing key portions of his election-related executive order to move forward while litigation continues.
California Attorney General Rob Bonta is co-leading a coalition of 24 state attorneys general seeking emergency court intervention to stop the Postal Service’s new requirements.
And with roughly 80% of California voters using mail ballots in the 2024 election, the stakes could hardly be higher.
California Launches New Fight Over Mail-In Voting
The latest showdown centers on new Postal Service requirements designed to change how mail ballots are processed.
The rules stem from Trump’s March 31 executive order aimed at tightening procedures surrounding voting by mail and verifying voter eligibility.
Under the new system, states would be required to enroll eligible mail voters with USPS. The Postal Service would then maintain state-specific lists identifying those voters.
The rules also establish new requirements for ballot envelopes.
USPS would not transmit certain ballots when voters aren’t included on the required lists or when ballot envelopes fail to comply with the new federal standards.
California and other states say that goes far beyond the Postal Service’s proper role.
Newsom Administration Goes After USPS
California Attorney General Rob Bonta announced the new lawsuit Wednesday, co-leading a coalition of attorneys general challenging the USPS rule.
The coalition is asking a federal court for both a temporary restraining order and preliminary injunction that would prevent the requirements from taking effect while the case is litigated.
Bonta blasted the policy as federal overreach.
“This mail-in voting rule is an unlawful overreach that shows just how far President Trump will go to control elections,” Bonta said.
He maintains that states have constitutional authority to administer elections and argues that neither the president nor the Postal Service can simply assume that power.
California Gov. Gavin Newsom also weighed in, declaring that California would continue fighting the administration’s election policies.
But supporters of Trump’s approach see the issue differently.
The administration has presented the changes as election-integrity measures intended to strengthen safeguards surrounding mail ballots and voter eligibility.
That leaves the courts confronting a much larger question: How much authority does the federal government have over the mechanics of voting by mail?
Supreme Court Hands Trump a 6-3 Victory
California’s latest lawsuit comes immediately after a major Supreme Court development.
On August 24, the Supreme Court voted 6-3 to grant the Trump administration’s request to stay a lower-court injunction that had prevented portions of Trump’s executive order from being implemented.
That means the administration can move forward with key parts of the order while the legal battle continues.
But there’s an important distinction.
The Supreme Court did not rule that Trump’s executive order is constitutional.
Instead, the majority concluded that the states’ original lawsuit had been brought prematurely because some of the federal government’s proposed actions had not yet been implemented.
With USPS now issuing its final rule, California and the other states have launched a fresh legal challenge aimed directly at those regulations.
In other words, the Supreme Court decision didn’t end the fight.
It helped trigger the next round.
What Trump’s Mail-Voting Order Does
Trump’s March executive order calls for significant changes to the federal government’s involvement in election administration.
Among other provisions, it directed federal officials to compile voter-eligibility information and instructed USPS to establish new procedures involving mail ballots.
The Postal Service announced its final rule in August.
Under the new requirements, states would have to provide voter information so eligible mail voters can be enrolled with USPS.
Ballot envelopes would also have to comply with new federal design and identification standards.
The Trump administration argues that tighter procedures can strengthen election security and help ensure that ballots are handled properly.
California and other Democratic-led states counter that the federal executive branch is attempting to exercise powers it does not possess.
That constitutional dispute could ultimately determine the future of the policy.
Why California Is Fighting So Hard
California has more riding on the dispute than most states.
Voting by mail is deeply embedded in the state’s election system.
About 80% of California voters cast their ballots through the mail during the 2024 general election.
Any significant change to how those ballots are mailed, returned or processed could therefore affect millions of voters and force election officials to make substantial changes to existing procedures.
California originally sued over Trump’s executive order in April.
A federal judge subsequently blocked important provisions of the order, handing California and the other states an early victory.
The Supreme Court’s August ruling temporarily removed that obstacle.
Now the states are attacking the USPS regulations themselves.
California’s Mail Ballot System Already Faces Questions
The battle comes as California’s massive vote-by-mail operation faces scrutiny over rejected ballots, election deadlines and lengthy counting periods.
Nearly 150,000 mail ballots were rejected during California’s June primary, according to an Associated Press analysis.
More than 93,000 reportedly arrived too late to be counted.
Other ballots were rejected for reasons including signature problems, duplicate voting and other deficiencies.
Those figures highlight a reality sometimes lost in the political argument over mail voting: sending in a ballot doesn’t necessarily mean that ballot will ultimately be accepted.
Election officials must still determine whether each ballot satisfies applicable state requirements.
Slow Vote Counting Remains a Political Flashpoint
California’s lengthy ballot-counting process has also attracted criticism.
While many states report the overwhelming majority of their election results relatively quickly, California races can remain undecided for days or even weeks as officials process large numbers of mailed ballots.
State officials maintain that the process prioritizes accuracy and gives eligible voters an opportunity to resolve certain ballot problems.
Critics argue the delays can undermine public confidence, particularly when closely watched races remain unresolved long after Election Day.
Whatever one’s view, California’s dependence on mail voting makes changes involving USPS particularly consequential.
Election Fraud Allegations Add Another Layer
The political atmosphere surrounding California elections has become even more heated following allegations connected to the June primary.
Federal prosecutors opened multiple investigations into alleged election fraud, while a federal prosecutor was sent to observe ballot processing in Los Angeles.
The existence of an investigation does not establish that fraud occurred, and allegations must be proven with evidence.
Still, the investigations are likely to fuel the broader national debate over election integrity, ballot security and public confidence in the voting process.
Those issues have become increasingly contentious as mail voting has expanded across the country.
States’ Rights Versus Federal Election Security
The legal battle ultimately extends well beyond California.
At its core is a constitutional argument about who gets to make election rules.
California maintains that states possess primary authority to administer elections and that the Postal Service cannot create a new federal system determining which mail ballots it will transmit.
The Trump administration’s position is that the executive branch can take lawful steps to protect federal elections and improve the integrity of mail-ballot procedures.
That puts two major principles into direct conflict: state control over election administration and federal efforts to enforce election safeguards.
The Supreme Court’s first ruling didn’t resolve that constitutional question.
The next round of litigation may get much closer.
Mail-In Voting Battle Could Head Back to Supreme Court
With the November midterms approaching, time is becoming increasingly important.
Election officials need to know which rules they are expected to follow before ballots begin moving through the mail.
California and its allies want a judge to stop the USPS requirements before they disrupt existing election procedures.
The administration, meanwhile, has scored an important procedural victory at the Supreme Court and is moving ahead with its election-integrity agenda.
That makes another high-stakes court battle increasingly likely.
And considering the constitutional questions involved, few should be surprised if the dispute eventually lands before the Supreme Court again.
For California, the battle is about preserving its existing vote-by-mail system and state control over elections.
For the Trump administration, the changes are part of a broader effort to tighten election safeguards and voter-eligibility procedures.
For voters, the most important question is much simpler:
What rules will actually be in place when it’s time to cast a ballot?
With the midterm elections rapidly approaching, America’s latest fight over mail-in voting is far from settled.
