PHOENIX -- Arizona will no longer participate in a multistate program that compares voter registration lists in search of duplicates, the state's top elections administrator said Tuesday.

In a letter to the program's administrators, state elections director Sambo Dul formally gave notice that the state would end its decade-long affiliation with the Interstate Voter Registration Crosscheck program.

The program, informally known as Crosscheck, was founded in 2005 by then-Kansas Secretary of State Ron Thornburgh (R). It was meant to compare voter records in multiple states with the goal of reducing duplicate or outdated voter registrations, as can occur when a voter moves to a new state and registers to vote, but fails to cancel their previous registration.

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But Crosscheck became more controversial under Thornburgh's successor, Kris Kobach (R), who helped grow the program to 29 states across the country. Voting rights groups said the program routinely returned false positives, unjustly canceling legitimate voter registrations.

The American Civil Liberties Union (ACLU) of Kansas filed a class action lawsuit against Kobach in 2018, alleging that his office violated voters' privacy through the Crosscheck system. The ACLU said Crosscheck cancellations are false positives in 99 percent of all cases.

Arizona Secretary of State Katie Hobbs (D), Dul's boss, cited those privacy concerns in canceling the state's participation.

"I am not willing to take any chances with the security and accuracy of our voter registration list. I want to make it absolutely clear that we are not sending information to Crosscheck. Arizona voters will not be put at risk of having their voter registration wrongly canceled based on inaccurate information," Hobbs said in a statement.

Arizona has not sent any data to Crosscheck administrators since 2017, under Hobbs's predecessor, Michele Reagan (R).

But Dul said data that Arizona previously sent to Crosscheck administrators could still be used to cancel voter registrations in other states. Dul asked the administrators to delete any Arizona data that remains in the national database.

Arizona is the 9th state to drop out of the Crosscheck program. The state is one of 26 states to share data under a different program, the Electronic Registration Information Center, a nonprofit group formed with assistance from the Pew Charitable Trusts in 2012.