PHOENIX — Longtime Republican Sen. John McCain made one last campaign stop Monday as he seeks his party’s nomination against two primary election opponents ahead of what is shaping up to be a strong general election challenge.

The 2008 GOP presidential nominee visited a Phoenix fire station for an endorsement from the Professional Fire Fighters of Arizona and then rallied volunteers at his campaign headquarters.

Looming in the background is former state Sen. Kelli Ward, who lags in the polls but has mounted an aggressive primary challenge to McCain, who turned 80 on Monday.

Ward has been mainly ignored by McCain, who is looking to November when he faces off against a well-funded Democrat in Rep. Ann Kirkpatrick — if he wins Tuesday’s primary election.

Asked about recent Ward comments that questioned his life expectancy and said he’s too old for the job, McCain punted.

“I’ll let the people of Arizona who know me very well make that judgment,” McCain said.

Ward has cast the race as a David and Goliath battle, one that “David won.”

“The overwhelming message is it is time for Sen. McCain to retire and it’s time for new blood to go into Washington D.C. and the people overwhelmingly want to vote for Kelli Ward,” she said in a recent interview.

Also on the Republican ballot is radio talk show host Clair Van Steenwyk, along with Alex Meluskey, who suspended his campaign early this month.

Other races drawing national interest in Arizona include a bid for a seventh term by combative Maricopa County Sheriff Joe Arpaio. The sheriff has nearly $10 million in his war chest and hopes voters ignore a federal judge’s recent order referring him for criminal contempt of court charges.

U.S. District Judge Murray Snow’s Aug. 19 ruling came in a long-running case where the sheriff acknowledged he failed to stop his signature immigration patrols despite Snow’s order to halt them.

He faces three Republican challengers on Tuesday: Former Buckeye Police Chief Dan Saban, retired sheriff’s Deputy Wayne Baker and Marsha Hill, former commander of a sheriff’s volunteer group.

All nine U.S. House seats are also on the primary ballot, although the Republican battles for the 1st, 4th and 5th districts and the Democratic race for the 2nd district are the tight ones.

In the 1st District, five Republicans are vying for the chance to advance to the General Election and face the Democrat seeking Kirkpatrick’s seat. They are Gary Kiehne, Ken Bennett, Paul Babeu, Shawn Redd and Wendy Rogers. Arizona House Speaker David Gowan suspended his campaign but remains on the ballot.

The 4th District features a primary challenge to three-term Rep. Paul Gosar. Former Buckeye City Councilman Ray Strauss has benefited from more than $280,000 in spending from a group that seeks to unseat “freedom caucus” members who ousted House Speaker John Boehner.

The 5th District features a four-way race among Republicans who want to replace retiring Rep. Matt Salmon in the heavily GOP district in the eastern Phoenix suburbs. Voters will choose between Christine Jones, Andy Biggs, Justin Olson and Don Stapley.

In the 2nd District, Democrats Matt Heinz and Victoria Steele are vying for a chance to go up against incumbent U.S. Rep. Martha McSally, a first-term Republican who won the seat by only 167 votes in 2014. The November contest is expected to be competitive and one of the most closely watched in the nation.

The other statewide race features a five-way race among Republicans seeking three seats on the state’s utility regulation panel, the Arizona Corporation Commission. The candidates are incumbents Bob Burns and Andy Tobin and commission hopefuls Al Melvin, Rick Gray and Boyd Dunn.

Polls open at 6 a.m. and close at 7 p.m., with first results expected just after 8 p.m.