ST. PAUL — Conservative critics of Minnesota’s same-day voter registration system told a federal judge it allows too many ineligible people to cast ballots.

U.S. District Judge Donovan Frank heard oral arguments Friday in the legal challenge to Minnesota’s popular voting program. Conservative groups and a GOP state lawmaker sued alleging problems are so serious that federal courts should order changes.

Attorney Erick Kaardal argued the state should require election officials to check databases on all same-day registrants to determine if they’re eligible, or else require them to cast “provisional” ballots.

State and county lawyers argued that would disenfranchise large numbers of people who register on election day, and said plaintiffs lack proof of their allegations.

Frank says he’ll rule within two months.