(CNN) The Supreme Court ruled Monday that President Donald Trump may begin implementing parts of an executive order to restrict mail voting, though further legal hurdles remain before the November midterm elections.While the co urt described the order as limited, the decision creates new uncertainty regarding midterm voting rules. It allows for the possibility that Trump will eventually impose policies from a March order that gave the U.S. Postal Service and the Department of Homeland Security unprecedented roles in election management.The justices issued a 10-page unsigned opinion Monday over the dissent of the courts three liberal justices. The ruling allows the Trump administration to proceed with a DHS proposal to compile state-specific lists of people the agency believes are eligible to vote. This specifically affects Democratic-led states that challenged the plan in court.Another section of the executive order requires states sending ballots through the mail to submit lists of eligible voters to the Postal Service. It also mandates tracking barcodes on ballot envelopes. While the Supreme Court gave the U.S. Postal Service the green light for this plan, a lower court has already blocked that specific effort nationwide in a separate case.Additional court action is likely required before the USPS can move forward. These legal battles could lead to new emergency appeals reaching the Supreme Court within days. Consequently, Mondays ruling is unlikely to be the final word on the executive order.The court noted in its order that states retain the right to challenge any final Postal Service rules that cause them harm.The decision focused on the timing of the legal challenge rather than the legality of the executive order itself. Trump has made yearslong unsubstantiated claims of voter fraud while attempting to reduce confidence in mail-in voting.The court wrote that its decision on this specific application does not guarantee that every measure taken to implement the order is lawful. The justices noted that only time will tell on that front.The ruling is a loss for Democratic states, which warned they must now divert resources away from election preparation.Steve Vladeck, a CNN Supreme Court analyst and professor at Georgetown University Law Center, said the ruling is a temporary win for Trump but does not fully clear the way for his mail-in ballot restrictions. He noted that a Massachusetts district court could block the underlying USPS rule as early as Tuesday.Jackson: Kafkaesque nightmareElection cases have grown increasingly contentious at the Supreme Court this year. In a high-profile case in late April, the 6-3 conservative majority significantly weakened the Voting Rights Act regarding Louisianas congressional districts.The liberal justices dissented from Mondays decision. Justice Sonia Sotomayor, joined by Justice Elena Kagan, argued that lower courts should have been allowed to rule in favor of the states now. Sotomayor emphasized that the majority did not address whether Trumps attempts to interfere with the 2026 elections are lawful or if the executive branch has the constitutional authority to implement such directives. She characterized the decision as merely delaying the inevitable legal adjudication of those challenges.Justice Ketanji Brown Jackson wrote a separate, lengthy dissent, arguing the ruling creates unnecessary chaos for the upcoming midterms. She criticized the conservative majoritys inconsistent approach to the timing of election cases, describing the legal precedents as a Kafkaesque nightmare. Jackson noted that while the court often rejects challenges for being too late, it is now rejecting them for being too early, despite the proximity of the election and the presence of ongoing harm.Next stepsTrump signed the executive order in March, directing the USPS and DHS to screen voter rolls for non-citizens and regulate mail ballot programs. While the Justice Department argued the move ensures election integrity, the Democratic-led states that sued called the effort an extraordinary threat to democracy.Under the Constitution, Congress and the states determine voting procedures rather than federal agencies or the White House.The presidents order requires states to provide voter lists to the U.S. Postal Service, which would then be prohibited from delivering ballots to anyone not on those lists. It also mandates tracking barcodes and prioritizes federal prosecution for election officials who process ballots for ineligible voters.The order also tasks the DHS with creating its own lists of eligible U.S. citizens. Administration officials suggested in court filings that while failing to use these lists might not be a crime, it could serve as evidence in prosecutions related to non-citizen voting.Trump has promoted conspiracy theories about mail voting for years to discredit his 2020 election loss. However, improper voting is extremely rare, and the administration has not provided evidence of fraud on a scale that could alter any election outcome.Federal courts in Boston initially blocked the order in 23 states, but a Washington, D.C., appeals court allowed it to proceed. Trump filed an emergency appeal with the Supreme Court on July 27. Meanwhile, Judge Indira Talwani in Boston issued a preliminary injunction in a separate case brought by advocacy groups, blocking the USPS directives nationwide.The Justice Department asked the Supreme Court to rule in a way that would force lower courts to side with the government in all related lawsuits. However, the justices provided little of the guidance Trump officials sought.In the appeal, the Trump administration focused on timing rather than legality. The Justice Department argued the lawsuit was not ripe because final regulations from the Postal Service and DHS were not yet complete.That changed Friday when the USPS issued a 95-page rule. The document confirmed the agency will only deliver mail ballots if envelopes have tracking barcodes and voters are enrolled in a new eligibility portal. This rule undercut the governments argument that a lawsuit was premature, especially as some states must begin mailing ballots in a few weeks.Sparring over harmThe conservative majority sided with Trump, concluding that states had not yet proven they were harmed by the directives. At the time of the initial block, the agencies had not finalized their implementation plans.The Supreme Court noted that the order does not require states to use the DHS lists, stating the plan does nothing to them. The justices also noted it was unclear at the time of the filing if the USPS would even issue final regulations.The liberal justices disagreed, stating the states showed harm even in the early stages of litigation. Sotomayor pointed to threats of prosecution against election officials, writing that states face a credible threat of investigation if they refuse to use the DHS lists to vet voter rolls. ...read more read less