On December 10, 2016, Nirenberg became the first primary challenger to Ivy Taylor for her position as mayor of San Antonio. On May 6, 2017, the first round of voting was held, with no candidate reaching the required majority of 50% of the vote. Nirenberg and Taylor finished with the two highest vote totals and advanced to a runoff election held June 10, 2017. Although Nirenberg trailed Taylor in the primary vote, he went on to defeat Taylor 54.59-45.41%. In so doing, Nirenberg became the first person in twenty years to defeat an incumbent mayor of San Antonio who sought re-election.
2019 San Antonio mayoral race
Nirenberg declared his candidacy for re-election to the office on January 29, 2019. His primary opponent was identified as Greg Brockhouse, a member of the San Antonio City Council who also took office in 2017 and frequently objected to Nirenberg's platform. The election was scheduled for May 4, 2019, but since no majority was reached by any candidate, a runoff election was scheduled for June 8. In the runoff, Nirenberg was elected to a second term, defeating Brockhouse by a 51.11% to 48.89% final vote.
Tenure
Although Nirenberg identifies as an independent and ran for office as a nonpartisan politician, he was considered to have run on a more progressive platform. In 2013, Nirenberg endorsed a city ordinance which bans discrimination based on gender identity and sexual orientation. Taylor, then also a member of the city council, voted against the ordinance. Taylor also opposed the city's filing of a lawsuit against the new state law which defines a misdemeanor offense for municipal officials who refuse to cooperate with federal authorities seeking to halt illegal immigration. Signed by GovernorGreg Abbott, the law targets the sanctuary city movement. Nirenberg, conversely, backs the lawsuit. As mayor-elect, Nirenberg called upon the city council to endorse the Paris climate accord even though U.S. President Donald Trump announced plans to remove the United States from the agreement. The San Antonio City Council approved a resolution to sign the Paris climate accord one day after Nirenberg's election, and in November 2017, the City Council approved the creation of a Climate Action and Adaptation Plan. This would lead to San Antonio being one of 25 cities awarded the American Cities Climate Challenge grant in 2019 by Michael Bloomberg. In 2019, Nirenberg led the charge to have a Chick-fil-A restaurant removed from the concessions contract at the San Antonio International Airport, citing a conflict with the company's opposition of same-sex marriage. Councilman Greg Brockhouse opposed this decision and called for a re-vote on the decision but it was defeated. Texas Attorney GeneralKen Paxton later began an investigation on the actions of Nirenberg and the San Antonio City Council, claiming the decision was in violation of existing Texas laws, the U.S. Constitution, and even San Antonio's own ethics code. The Federal Aviation Administration also opened an investigation on this action. On June 10, 2019, Texas governor Greg Abbott signed into lawSenate Bill 1978, colloquially known as the "Save Chick-fil-A Bill", which forbids local governments from taking adverse steps against companies or individuals based on their religions beliefs. On September 5, a group of five individuals filed suit against the City of San Antonio citing this new law.
Personal life
Nirenberg is married to Erika Prosper, director of customer insights for H-E-B. The couple has one son, Jonah.