While the secretary of state has cleared independent candidate Herbert Hoffman to remain in the U.S. Senate race, the legal debate over whether he has collected enough signatures to appear on the November ballot revealed troubling shortcomings in the state’s validation process. These problems should concern lawmakers as two controversial people’s veto campaigns will soon submit their signatures.

The Secretary of State’s Office ruled late last month that Hoffman, a retired psychologist from Ogunquit, filed a sufficient number of valid signatures to earn a spot on the ballot. On June 5, John Knutson, the chairman of the state Democratic Party, filed a challenge alleging that many of the signatures gathered by Mr. Hoffman were invalid. Mr. Hoffman submitted 4,112 signatures, slightly more than the 4,000 required by state law to appear on the ballot.

Last week, the Secretary of State’s Office held a hearing on the matter. An early contention was that Mr. Knutson, because of his leadership position in the Democratic Party, was not qualified to bring a challenge. Mr. Hoffman sought to enter the race in which 1st District Rep. Tom Allen, a Democrat, seeks to unseat Republican Sen. Susan Collins. His anti-war, pro-impeachment stance makes it likely he would take more votes away from Rep. Allen than Sen. Collins.

The hearing then focused on the substance of the case. Mr. Hoffman admitted that 56 signatures he submitted were duplicates and that he was not always in the presence of people who signed petitions, a requirement of state law.

After the hearing, Deputy Secretary of State Julie Flynn reported that 74 of Mr. Hoffman’s signatures were invalid, 60 of them because they were duplicates. Others were rejected because the signers were not registered voters or the writing was illegible.

Three signatures were rejected because these people testified at the hearing that Mr. Hoffman was not present when they signed his petition. The Democratic Party argues that the law requires an entire page of signatures be thrown out when a candidate improperly swore that he or she was present when the signatures were collected. If all these signatures were invalidated, Mr. Hoffman would fall short of qualifying for the ballot.

Secretary of State Matthew Dunlap accepted Ms. Flynn’s conclusions Monday, allowing Mr. Hoffman to stay on the ballot. That decision can be appealed in court.

Relying on challenges to find invalid signatures is not a good way to determine whether candidates or referendums can appear on the ballot. In this case, the Democratic Party entered all the signatures into a computerized spreadsheet and was easily able to detect duplicates. Manually reviewing the signatures, which the Secretary of State’s Office largely relies on town clerks to do, is far from foolproof.

With a growing number of signature gathering campaigns to get measures on the ballot, a better review process is needed.