Five candidates are running in the Republican primary for United States Senate in Arizona on August 2, 2022. Incumbent Mark Kelly (D) is running for re-election.

Mark Brnovich, Jim Lamon, and Blake Masters have led in polling, fundraising, and media attention.

Brnovich, a career prosecutor, has served as Arizona’s attorney general since 2015. Before that, Brnovich served as an assistant attorney general from 1998 to 2003 and as the director of Arizona’s Department of Gaming from 2009 to 2013. Brnovich has highlighted the legal challenges his office has brought against President Joe Biden’s (D) tax and immigration policies, among others. TV show host Sean Hannity and radio host Mark Levin endorsed Brnovich.

Lamon is a businessman who founded DEPCOM Power, a solar energy company he sold in 2021. Lamon has largely self-funded his senate effort. According to Open Secrets, Lamon had contributed $13M to his campaign as of July 3, 2022, or 94% of all funds donated. Lamon has cited U.S.-China trade relations as a top issue, saying, “Communist China is the biggest threat to our economic security and national sovereignty.” The Conservative Political Action Coalition, the National Border Patrol Council, and a number of state legislators endorsed Lamon.

Masters is a tech entrepreneur who co-authored Zero to One: Notes on a Startup, a business book based on a class tech investor Peter Thiel taught at Stanford. Masters joined Thiel Capital in 2014 and was named president of the Thiel foundation in 2015. Masters has expressed support for increased regulation of technology companies and privatizing social security. Thiel, former President Donald Trump (R), and TV show host Tucker Carlson endorsed Masters.

All three candidates have cited border security as a top issue. Brnovich highlighted his record as attorney general, saying he challenged border measures implemented by the Biden administration, such as the 100-day pause on deportations. Masters said he would increase the size of the border patrol and use hi-tech surveillance at the border. Lamon said he would end sanctuary cities and called the border a “breeding ground for trafficking of illegal drugs, sex trafficking (including children), and even some known terrorists.” All three candidates said they supported finishing the construction of a border wall.

Brnovich and Lamon have criticized Masters for his relationship with Thiel. Brnovich said, “I know that the answer to Big Tech is not having someone that’s financed by Big Tech and made all their money in Big Tech.” Masters responded that his understanding of tech companies allows him to better confront them. “I know how it works,” Masters said.

In June, Saving Arizona PAC, a political action committee affiliated with Thiel, released an ad criticizing Lamon’s solar company for importing supplies from China and said the company was “associated with forced slave labor.” Lamon said everyone in the energy industry uses Chinese parts and added, “This ad paid for by Blake Masters’ big tech super PAC is ridiculous and comically hypocritical given Masters’ extremely recent and proactive business dealings with China.”

The 2020 presidential election has been a top issue in the race as well. Trump has criticized Brnovich, saying he hasn’t done enough as Arizona’s attorney general to investigate fraud in the election. Brnovich, who opened an ongoing civil investigation into the 2020 results in Arizona, said, “I understand [Trump’s] frustration, but as I’ve said previously, I will continue to follow the facts and evidence and do what the law requires.”

Masters said he believes Trump won the election. Lamon, who signed his name on a list of alternate Arizona presidential electors ahead of the 2021 Electoral College vote count, said he wouldn’t have voted to certify the election.

Three election forecasters rate the race a Toss-up, meaning the general election is expected to be competitive. The previous two Senate elections—held in 2018 and 2020—were both decided by 2.4 percentage points. In 2020, Kelly defeated incumbent Sen. Martha McSally (R) in a special election, 51.2% to 48.8%. In 2018, Kyrsten Sinema (D) defeated McSally, 50.0% to 47.6%.

Michael McGuire and Justin Olson are also running in the primary.