Opponent Jeff FlakeJeffrey (Jeff) Lane FlakeSenate GOP attempts to wave Trump off second Putin summit Senate approves resolution warning Trump not to hand over US officials Flake: Trump's Russia summit ‘truly an Orwellian moment’ MORE, the U.S. representative for Arizona's 6th district, has held a vast lead over Cardon for the duration of the race, but the most recent polling, taken in mid-May, showed Cardon surging to double-digit support — a significant improvement from previous polling that had shown him bringing in less than 10 percent support. That poll showed Flake's support dropping below 50 percent for the first time, potentially indicating that a barrage of attack ads put out by the Cardon campaign were taking their toll on Flake.

But with Flake still leading by double digits in that last poll, a win for Cardon is by no means assured. His underdog status, however, isn't deterring the candidate from continuing to campaign up until the election, Cardon spokeswoman Alyssa Pivirotto said.

"With just 3 weeks until the Arizona Republican primary, Wil Cardon is outworking every candidate in the US Senate race. He continues to tirelessly travel the state talking with Arizonans, attend as many candidate forums as humanly possible and reach out to voters over the phone and even visit their homes. Wil is not slowing down and neither is his campaign. While we would never reveal campaign strategy for the next 3 weeks, rest assured, Wil Cardon is in this race to win it," she said in a statement.