A state judge in Michigan partly rejected an effort to disqualify former President Donald J. Trump from running for president in the state, ruling that Mr. Trump would remain on the ballot in the Republican primary, and that the state’s top elections official does not have the authority alone to exclude him from the ballot.

But the judge appeared to leave the door open for a future battle over Mr. Trump’s eligibility as a candidate in the general election, saying that the issue “is not ripe for adjudication at this time.”

The ruling notches a preliminary victory for Mr. Trump in a nationwide battle over his eligibility to run for president again.

Plaintiffs across the country have argued that Mr. Trump is ineligible to hold office again under Section 3 of the 14th Amendment, which disqualifies anyone who “engaged in insurrection or rebellion” against the Constitution after having taken an oath to support it, citing his efforts to overturn the 2020 election.

This is a developing story. Check back for updates.