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The outcome of the Arizona Senate race between Republican Martha McSally and Democrat Mark Kelly could determine whether President Trump's nominee to replace late Supreme Court Justice Ruth Bader Ginsburg makes it through the Senate, former federal prosecutor Andy McCarthy told "Bill Hemmer Reports" Monday.

"There's a 53-47 Republican edge [in the Senate] right now, but that may not last for very long after the election," McCarthy explained. "The election in Arizona, unlike the other Senate elections in the country this year, is a special election ... If Mark Kelly defeats Martha McSally, he could be a senator on November 30, which means the 53-47 edge during a lame duck [session] very quickly becomes 52-48.

"And then, if you consider all of the different challenges that are likely to happen after the election in terms of the mail-in balloting, which is kind of going to be unprecedented in the degree that we're going to have in this election," McCarthy added, "I think that really shortens the period of time that the Republicans have the kind of edge that they have now, which is narrow enough as it is.

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"I think they have a better chance of getting this nomination through before Election Day than after."

The winner of the McSally-Kelly race will serve out the term of the late Sen. John McCain, who died in August 2018 after being reelected two years earlier. McSally was appointed to the Senate by Arizona Republican Gov. Doug Ducey at the start of 2019 after former GOP Sen. John Kyl took McCain's place and served out the remainder of 2018 before resigning.

A Fox News Poll released earlier this month showed the insurgent Kelly 17 points ahead of incumbent McSally, in what was once a reliably Republican seat.

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Two Republicans, Susan Collins of Maine and Lisa Murkowski of Alaska, have already said that whoever wins the presidential election in November should nominate a replacement for Ginsburg, who died Friday at the age of 87.

McCarthy noted that if just four Republicans oppose a potential Trump nominee, Senate Majority Leader Mitch McConnell, R-Ky., "is sunk."

"The most important thing, because this is politics, is 'does he have the votes? ... '" he said. "The problem is that this is a difficult vote for some people who are in difficult races. It may actually help other candidates -- it depends on the state -- but a lot has to factor into that."