The notifications would go to voters registered with parties, but were inspired by the many reports of independent “no party preference” voters who failed to request special ballots in time to vote in the June 2016 primary between Democrats Hillary Clinton and Vermont Sen. Bernie Sanders. Clinton went on to a resounding victory. A group of Sanders supporters, angered by what they saw as confusing rules on how unaffiliated voters could vote in the Democratic primary, tried to convince a federal judge that spring to allow voter registration all the way until election day. The judge ultimately rejected the request.

Source: Los Angeles Times April 02, 2019 18:00 UTC