The Supreme Court and the Republican-controlled Senate have erected guardrails that limit President Donald Trump’s ability to make it harder for citizens to vote, and he’s not happy about that.

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In a 5-4 decision handed down Monday, Chief Justice John Roberts, who was appointed by Republican President George W. Bush, and Justice Amy Coney Barrett, who was appointed by Trump, joined the court’s three liberals in ruling against the Republican National Committee’s challenge to a Mississippi law that allows certain ballots to be tallied if they are received after Election Day.

Civil rights groups hailed the decision as a protection for voters.

“Our democracy is stronger when more people, not less, can participate,” Robert Weiner, the Voting Rights Project director of the Lawyers’ Committee for Civil Rights Under Law, said in a statement.

But Trump, who has contended contrary to the evidence that Democrats “rigged” his loss in the 2020 election, said Monday that the majority decision is “very detrimental to honest elections” and claimed that it “gives people more time to vote illegally.”

He used the courtroom defeat to redirect attention to the Senate, where his effort to rewrite voter-eligibility laws is stuck. Republicans do not have enough votes to either pass the so-called SAVE America Act or kill the chamber’s rule requiring 60 senators to overcome a filibuster.

That legislation is “even more important” as a result of the ballot decision, Trump said. Earlier in the day, in a Truth Social post, he sought to apply more pressure to Senate Republicans to act on his bill, which would require multiple forms of identification to register to vote and photo ID to cast a ballot.

“In a time when there is a powerful Communist Movement taking place in our Country, one more dangerous than World War I, World War II, Pearl Harbor, or September 11th, all Dumocrats, and our five Republican Senate Hold Outs, Lisa Murkowski, Susan Collins, Thom Tillis, Bill Cassidy, and Mitch McConnell must vote to SAVE OUR COUNTRY,” he wrote of GOP senators from Alaska, Maine, North Carolina, Louisiana and Kentucky.

The Mississippi ruling was one of several on Monday that went against Trump — even as he won a major expansion of presidential authority to fire officials appointed to leadership posts at federal agencies deemed by Congress to be independent.

But Trump was optimistic that his side would prevail Tuesday on a pair of issues that were central to his 2024 campaign and which will be decided in a final batch of opinions issued by the court for this term: birthright citizenship and banning transgender athletes from competing in girls’ and women’s school and college sports.

On the first day of his term in January 2025, Trump signed an executive order to cancel automatic citizenship for children born to parents who were in the U.S. illegally. The move, which critics say contradicts the 14th Amendment’s guarantee of citizenship to “all persons” born in the country, is part of his broader effort to crack down on illegal immigration. The court will rule Tuesday on whether his executive order can stand.

In remarks to the media Monday, Trump said that it would be “extremely destructive” if the court rules against his order. And though he has often lobbied the court through his public remarks, criticized justices when they rule against him and challenged the powers of the other branches of government, he acknowledged on Tuesday that the high court is the final authority on the matter.

“It’s the Supreme Court, so I’ll accept,” he said.

The justices are also set to rule Tuesday on whether state bans on transgender girls and women competing in school and college sports are consistent with the Constitution. Trump campaigned on supporting such prohibitions.

With those cases still pending, Trump focused Monday on what he described as a major victory for the power of the presidency. In a case involving his firing of Federal Trade Commissioner Rebecca Slaughter, the court made clear that the president has broad authority to dismiss officials appointed to the boards of independent agencies.

The decision overturned a 91-year-old principle, called the “Humphrey’s Executor,” in which justices had held that the law did not allow President Franklin Roosevelt to fire an FTC commissioner simply because he had been appointed by President Herbert Hoover.

“What text, history, and structure settle, the Court’s precedent confirms — the President may remove his subordinates at will,” Roberts wrote for the majority. In practical terms, the decision expands the authority of presidents to sack administration officials, even if they serve at agencies that Congress set up to be independent of the Oval Office.

Trump wrote several Truth Social posts about the case on Tuesday before he addressed the media.

“This was the ruling that really topped everything by a lot today,” he said.

At the same time, the justices gave a reprieve to Lisa Cook, a member of the Federal Reserve Board whom Trump has tried to fire. That opinion, also written by Roberts, essentially created a Federal Reserve exception to the decision in the case involving other independent agencies.

Trump had argued that he should be able to remove Cook for cause because he has alleged that she committed mortgage fraud — a claim that she denies — and that her lawsuit to keep her job should not have been reviewable by the courts. The law establishing the Federal Reserve dictates that the president may only remove a governor “for cause.”

In leaning on that phrase, the court provided a road map for how Trump might fire Cook in the future, and he suggested in a Truth Social post that he would look for legal cause.

“We will take appropriate action immediately to make sure that someone who has committed wrongdoing will not be making vital decisions concerning the Welfare of the United States of America!” he wrote.

While Trump’s authority in the Oval Office expanded with the affirmation that he can choose who serves in his administration, he was handed a major defeat on the matter most personal to him.

The justices chose not to take up his appeal of a jury’s finding that he sexually abused and then defamed the writer E. Jean Carroll, effectively rejecting his claim. The jury in the civil suit awarded Carroll $5 million.

Trump left it to his legal representatives to address that loss.

“The American People stand with President Trump as they demand an immediate end to all of the Witch Hunts, including the Democrat-funded travesty of the Carroll Hoaxes,” Trump’s legal team said in a statement provided to NBC News. “President Trump will keep winning against Liberal Lawfare, as he continues to focus on his mission to Make America Great Again.”

Carroll’s lawyer, Roberta Kaplan, said that it was a victory for her client, not Trump.

“Today’s Supreme Court decision affirms once and for all the jury’s unanimous verdict that President Donald J. Trump sexually assaulted and defamed E. Jean Carroll,” Kaplan said in a statement. “His multiple efforts to appeal that verdict have all failed and today’s ruling ends his quest to avoid accountability for his actions.”