California’s presidential primary offered a vigorous test for Los Angeles County’s new election setup Tuesday, as throngs of voters showed up to cast ballots using the county’s first wholly redesigned system in more than a half-century.

Whether voters would understand the changes, and whether they would work as promised, made the stakes that much higher in an election already described as historic.

Nor were the challenges confined to L.A. By midday, state elections officials reported that 15 counties had experienced problems with their computer systems connecting to California’s statewide voter database. While voters could still cast ballots, the problem meant there was no way to update registration records or show that a citizen had voted. To avoid any chance of someone voting more than once, some locations were asking voters to cast provisional ballots — a fail-safe method of voting in which eligibility is confirmed after election day and before the vote is counted.

Should it persist, the lack of online connectivity at polling places and vote centers, would pose a problem for one of California’s most talked-about election changes: election-day registration, designed to ensure that any eligible citizen can still vote before polls close at 8 pm.

Read the full story on LATimes.com.