DES MOINES, Iowa (AP) — Iowa’s upcoming primary will mark the first statewide test of a new law that requires voters to show identification at the polls. State officials and voting advocacy groups say they’re keeping a close watch on its rollout Tuesday.

The law, which was passed last year and is being phased in, requires voters in 2018 to be asked for approved ID to vote. If someone doesn’t have that identification, they can sign an oath verifying their identity and cast a regular ballot.

A person without proper identification in 2019 will have to vote by provisional ballot. That requires the voter to return within a few days with ID or the ballot won’t count. Voting advocacy groups are monitoring the law’s implementation, and several county elections officials say they’ve done extensive training and outreach.