Amid the national debate over the integrity of mail-in elections, Los Angeles political reporter Michael Blood obtained state data showing 102,000 mail ballots for California’s March presidential primary were rejected for lateness or other mistakes. In his exclusive report, Blood showed that mail-in voting can be fraught with problems at a time when the pandemic is driving many states to gear up for near-universal vote-by-mail in November, and as President Trump casts doubt on the system’s validity. The story played widely online and The New York Times flagged the story on its live election briefing.