The U.S. Supreme Court ruled in favor of President Trump’s executive order increasing election integrity relating to mail ballots on Monday, saying states suing over the order did so improperly.

Today’s ruling is not the final action but comes as some states begin sending ballots to voters in early September. The opinion was issued in an unsigned order with the three liberal justices dissenting.

In March, President Trump signed the executive order in question directing the Department of Homeland Security to verify citizenship in each state. The order also directed the U.S. Postal Service (USPS) to initiate rulemaking to ensure only verified, eligible voters would receive ballots.

Last week, the USPS published their series of requirements in preparation of the order being allowed to go into effect.

“President Trump is taking decisive action to prevent non-citizens from voting in Federal elections and to protect the security of mail-in and absentee ballots,” a fact sheet summarizing the actions contained in the executive order stated.

The Supreme Court made clear it was not ruling on the merits of Trump’s order but took issue with the process. “On that score, time will tell,” the opinion reads, but adds the order itself did not harm the states suing Trump and that the Massachusetts district court lacked jurisdiction to bar it from taking effect because the order itself did not harm them at this point.