Arizona's nationally watched Senate race between Republican incumbent Sen. Martha McSally and Democratic challenger Mark Kelly has become one of the battleground state's costliest campaigns.

By the end of September -- before the two squared off in their first and only debate --  McSally had raised $50.9 million and Kelly raised $82.8 million, according to Federal Election Commission filings posted on Monday.

KELLY RAISES $39M, MCSALLY $23M IN ARIZONA SENATE RACE

That's a total of more than $130 million, which Cronkite News and CNN have reported positions the race as one of Arizona's most expensive ever. There are now just two weeks until Election Day, and early voting began in the Copper State on Oct. 7, reportedly garnering record-breaking turnout

Polling has shown the former NASA astronaut in the lead against fellow servicemember McSally for the past few weeks.

He has an edge of almost 8 percentage points at present, according to the Real Clear Politics average, though McSally has kept up a steady barrage of attacks against her opponent's platform and alleged ties to China

President Trump gave McSally's efforts a boost during the weekend, blasting Kelly on the campaign trail in Tucson and Prescott over his views on gun rights

Kelly, a military veteran, is married to former Congresswoman Gabrielle Giffords, who survived a mass shooting near Tucson in 2011. The pair co-founded a gun-safety group, now known as Giffords

 "I know the whole thing, the history, it's a sad thing," the president told a crowd of supporters. "But he's going to take away your guns, OK?"

Kelly's campaign website calls for stricter gun laws and promises to stand up to the gun lobby, advocate for red flag laws and universal background checks, and work to combat or reduce mass shootings and suicides. 

McSally, on the other hand, deemed herself the "Second Amendment Senator" on the debate stage, telling viewers she believed she had fired the largest gun of anybody in Congress

President Trump works the crowd after speaking at a campaign rally Monday, Oct. 19, 2020, in Tucson, Ariz. (AP Photo/Ross D. Franklin)

McSally also touted her work passing the 2017 Fix NICS Act, which penalizes government agencies for not reporting to the National Instant Criminal Background Check System, though noting that more needs to be done on mental health care.

The pair also squabbled over health care, the Supreme Court, the environment and social justice.

While McSally has aligned herself with the president, she is less popular in the state than he is.

And Kelly is leading her in key demographics, including women and Latinosaccording to Business Insider. She has the support of White voters and White voters without a college degree.

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The contest has been one to watch for Republicans and Democrats alike, as it is a key part of Democrats' plan to take control of the Senate from Republicans

In addition, because the race is technically a special election, Kelly could be sworn in as soon as Nov. 30 if he wins.

McSally reportedly has $12.1 million to spare and Kelly has $18.8 million, according to Cronkite News.

The Associated Press contributed to this report.