Donald Trump just suffered a major setback at the Supreme Court over one of his most aggressive attempts to reshape mail-in voting before the midterms.

And two conservative justices were furious about it.

In an unsigned order, the court refused to let the Trump administration immediately enforce a new set of Postal Service rules tied to absentee ballots, concluding that the government was “unlikely to succeed on the merits.”

The decision leaves the existing mail-voting system largely intact just weeks before Election Day.

Only Justices Samuel Alito and Clarence Thomas publicly dissented.

Notably, none of Trump’s three Supreme Court appointees — Neil Gorsuch, Brett Kavanaugh and Amy Coney Barrett — joined them.

That alone made the ruling politically striking.

Trump had signed an executive order in March directing the U.S. Postal Service to implement sweeping new procedures for election mail.

Among other things, the plan would have required states to provide the Postal Service with lists of eligible voters.

The Postal Service would then have been barred from delivering ballots to people who did not appear on those lists.

The administration also wanted ballot envelopes to carry tracking barcodes designed to make election mail easier to monitor.

Supporters said the changes would help detect fraud and improve ballot security.

Democratic-led states and voting-rights groups argued the rules could disenfranchise legitimate voters and create chaos if imposed too close to the November election.

For now, the challengers won.

The Supreme Court’s brief order did not provide a detailed explanation.

But Justice Brett Kavanaugh wrote separately to emphasize the timing problem.

He said the government might ultimately prevail on the broader legal issue, but state and local election officials simply did not have enough time to implement the changes before voters began casting ballots.

That practical concern proved decisive.

Alito strongly disagreed.

“The government has a strong interest in enforcing the rule,” he wrote.

He argued that the changes would improve the visibility of federal ballot mail and could help officials detect election fraud.

Alito acknowledged concerns about imposing a new system shortly before the midterms.

But he said those concerns were not enough to justify blocking the administration.

He also blamed the timing problem partly on the courts and the states challenging the rule.

According to Alito, litigation had delayed implementation for months.

He argued that challengers should not then be allowed to use that delay as a reason to stop the rule.

Thomas joined Alito’s dissent.

The two men have repeatedly been among the justices most receptive to Trump administration arguments.

But this time, they were clearly in the minority.

Trump’s own appointees did not save him.

That produced an immediate wave of celebration from Democrats and voting-rights advocates.

California Gov. Gavin Newsom called the ruling “a good day for democracy, the rule of law, and the American people.”

He said voters now had greater certainty about how the election would be conducted.

Senate Democratic leader Chuck Schumer was even more blunt.

He accused Trump of trying to make voting harder and said the president’s plan to alter mail voting was now dead.

Television commentators described the decision as a serious blow to Trump’s election strategy.

Rachel Maddow said implementing the new rules so close to the election could have created “chaos and confusion.”

CNN’s Kaitlan Collins similarly described the result as a major victory for voting-rights groups.

The Trump administration sees it very differently.

Trump erupted on Truth Social, calling the ruling “horrible” and “highly political.”

He praised Alito and Thomas as “legends” and accused the court of making it easier for Democrats to cheat through mail ballots.

There is no evidence of widespread mail-ballot fraud on the scale Trump routinely alleges.

Mail voting has been used across the United States for years, including in heavily Republican states, and election officials have repeatedly said fraud involving absentee ballots is rare.

Still, Trump has made opposition to mail voting one of his most persistent political themes.

He has repeatedly claimed the system is inherently vulnerable to manipulation.

At the same time, Republican campaigns have increasingly encouraged their own supporters to vote early and by mail.

That contradiction has become more pronounced as the 2026 midterms approach.

Trump wants tougher national restrictions.

Republican strategists also want to ensure their voters actually use every legal voting method available.

The Supreme Court decision now removes one of the administration’s biggest proposed changes from the immediate election calendar.

That does not necessarily end the legal fight forever.

The administration could continue pursuing the case after the midterms.

Kavanaugh’s concurrence explicitly left open the possibility that the government might ultimately prevail on some of the underlying legal questions.

But for November 2026, the immediate outcome is clear.

Trump’s proposed rules will not take effect in time.

That means states will not suddenly have to overhaul their mail-ballot procedures weeks before voting.

And that is exactly what Trump did not want.

The ruling is also notable because of who did — and did not — support him.

Trump appointed one-third of the Supreme Court.

Yet Gorsuch, Kavanaugh and Barrett all declined to join Alito and Thomas in trying to let the rules proceed.

For a president who regularly boasts about reshaping the federal judiciary, that makes the loss especially stinging.

Alito and Thomas wanted the administration’s plan to move forward.

The rest of the court did not.

And with the midterms rapidly approaching, Trump has run out of time to force through one of his most consequential election changes.