There was controversy surrounding the Arizona primary elections of 2016, specifically having to do with the decrease in polling places in Maricopa County from 200 in 2012 to only 60 in 2016, enacted by Republican officials despite the number of registered voters having increased from 300,000 in 2012 to 800,000 in 2016.

[10] Both the Clinton and Sanders campaigns, as well as the Democratic National Committee, sued the Arizona state government over the alleged voter suppression.

A Clinton win in Arizona was expected; she had beat Barack Obama in the state eight years earlier by a similar wide margin, and she generally performed well with minority voters in the 2016 primaries.

[24] Bernie Sanders made a late play for the state of Arizona, including airing Spanish-language ads featuring Congressman Raúl Grijalva.

[25] Hillary Clinton offset his efforts with advertising featuring former Congresswoman Gabby Giffords,[25] and airing radio ads in the Navajo language.