The state of Maryland has invalidated independent voters, forcing them to choose a political party or “unaffiliated” on their voter registration.

Letters went out last week in all of the state’s 24 counties to registered voters, informing them that the “independent” party is no longer recognized under Maryland’s state election laws. Voters who registered as “independent” are given two weeks to pick a party, or they will automatically be reverted to “unaffiliated” on their voter registration records.

Ross Goldstein, deputy administrator for the state elections board, said a previous group of officers who had registered the independent party in the state did not renew their registration records or any campaign finance reporting records. When that happened, Goldstein said, the party became decertified under state law.

Maryland is a closed primary state, meaning that voters must register as Democrats to vote in a Democratic primary, or as Republicans to vote in a Republican primary. For the general election, no affiliation is necessary. The laws are the same throughout all 24 counties.

National surveys first reported recognizable numbers of independent voters starting in the 1960s, especially in the Deep South and rural state areas. Numbers dipped after in the 1990s and 2000s, but about 30 percent of Americans still identify themselves as “independent.”

But Goldstein said state officials were worried that many voters had checked “independent” on their voter registration, such as when they registered a vehicle, when they really meant “unaffiliated.”

“There was a lot of concern about that,” Goldstein said. “There was a lot of unintended confusion about our registration forms.”

Voters in Maryland who wish to pick “unaffiliated” as their voter registration status have a stark choice: Goldstein and other state officials said the state only allows “unaffiliated” voters to vote in nonpartisan elections. In Maryland, that restricts the list almost completely to school board races.