Presidential candidate Ralph Nader secured a spot on Maryland's November ballot yesterday as the state's highest court ruled that election officials improperly rejected hundreds of signatures on petitions filed in support of his candidacy.

The Court of Appeals ordered that 542 disputed signatures be accepted, giving the Nader campaign and his Populist Party five more signatures than were required to win a spot on the ballot. The signatures had been rejected because they belonged to voters residing in counties other than those listed on the petitions they signed, a decision the Nader campaign challenged in court.

State Elections Administrator Linda H. Lamone, a Democrat, said yesterday that her office had "no vested interest" in the outcome of the case and that the ruling would not be appealed. A spokesman for the Nader campaign, Kevin Zeese, said that "the court made the right decision" and that Nader plans to campaign in Maryland on Friday.

Nader's campaign filed petitions Aug. 2 to create a Populist Party, but Lamone and local election officials invalidated about one-third of the signatures. The rejection left Nader supporters 537 short of the 10,000 valid signatures needed to qualify a new party for the ballot.

The campaign appealed in Anne Arundel County Circuit Court, where Judge Philip T. Caroom sided with the state.

Caroom noted that the Nader campaign filed its petitions on the day they were due, and he wrote that "the difficulty created by plaintiffs for themselves through last-minute petition filings" does not constitute a violation of their rights.

In a filing last week with the appellate court, Stephen Scavuzzo, the attorney for the Nader campaign and the Populist Party, wrote that "the outcome thus far is an offense to every American." He argued that disqualifying voters simply because their addresses do not match the state's election rolls was unconstitutional.

The Board of Elections argued that allowing local election boards to certify signatures in their counties prevents "a potential serious problem of voter fraud." The board and its attorney argued that voters might otherwise sign petitions in more than one county.

The Court of Appeals said yesterday that it would explain its reasoning in a forthcoming opinion. An order signed by Chief Judge Robert M. Bell said only that a majority of judges concurred.

According to Zeese, Nader is on the ballot in 36 states and the District. Pennsylvania's highest court yesterday ordered his name included on that state's ballot.

In seven of the states, Nader faces legal challenges from people who want him off the ballot. He is fighting in court to get on the ballots in seven other states.

In Virginia, election officials barred Nader from the ballot. The campaign has said it is reviewing that ruling before deciding what step, if any, to take.

Democrats are concerned that Nader will siphon votes from their nominee, Sen. John F. Kerry (Mass.), but Nader's presence on the ballot is unlikely to alter the outcome of the presidential contest in Maryland. The state is so heavily Democratic that Gov. Robert L. Ehrlich Jr. (R) recently said President Bush should not bother to campaign there.

In 2000, Democratic nominee Al Gore carried 57 percent of the state to Bush's 40 percent. A poll released last month by Gonzales Research and Marketing Strategies showed Kerry leading Bush in Maryland, 53 percent to 40 percent.

Staff writer David A. Fahrenthold and staff researcher Bobbye Pratt contributed to this report.

Candidate Ralph Nader is on the ballot in 36 states and the District.