McSally had consistently led in the count since Tuesday’s midterm elections, but hundreds of thousands of ballots remained outstanding as of Friday night, leaving the race in flux in a state where about three-quarters of voters cast ballots by mail.
The contest to replace retiring Sen. Jeff Flake (R-Ariz.) is one of three that remain unresolved nationwide. While Republicans are certain to control the Senate next year, the strength of their majority could be less than it appeared on Tuesday.
In the Senate race in Florida, the lead of Gov. Rick Scott (R) had narrowed to just more than 15,000 votes, or 0.18 percent, over Sen. Bill Nelson (D) as of Thursday night. That race is headed for a recount and could be mired in lawsuits.
Meanwhile, a race for a Senate seat in Mississippi is headed for a runoff on Nov. 27. Appointed Republican Sen. Cindy Hyde-Smith faces Democratic challenger Mike Espy. Both candidates had about 41 percent of the vote Tuesday.
As it stands, Republicans will hold at least 51 seats in the Senate come January, while Democrats will hold at least 46, including two that will be held by independents who caucus with the Democrats.
Depending on the outcome of the remaining three races, Republicans could hold as many as 54 seats, while Democrats could have as many as 49.
Republicans currently hold a 51-to-49 majority in the Senate.
In Arizona, four county Republican parties filed suit Wednesday to prevent county recorders from trying to verify signatures after polls closed for mail-in ballots.
That drew a rebuke from the wife of late Republican senator John McCain (R-Ariz.).
“I am one of those mail in ballots,” Cindy McCain tweeted Thursday at the Arizona GOP’s account. “I was under the impression my vote was always counted.”
Commenting on the Florida race, President Trump tweeted Thursday night in support of Scott after the Republican candidate filed lawsuits accusing the election supervisors in Broward and Palm Beach counties of possibly committing “rampant fraud.”
“Law Enforcement is looking into another big corruption scandal having to do with Election Fraud in #Broward and Palm Beach. Florida voted for Rick Scott!” Trump wrote.
Senate Minority Leader Charles E. Schumer (D-N.Y.) warned Trump and Scott against trying to influence vote-counting.
“In a democracy, no one — not even the President — can prevent the lawful counting of votes. We will not allow him or anyone else to steal this election,” he wrote of Trump on Twitter.
Parallels had emerged Thursday between Florida and Georgia, where the two parties were engaged in a similar battle over outstanding ballots and alleged voting irregularities in the governor’s race. Georgia Republican gubernatorial candidate Brian Kemp declared victory and resigned his position as the state’s top election official while votes were still being counted.
“Brian Kemp eventually realized that it’s completely inappropriate to use one’s official powers to influence one’s own election. Governor Scott should realize that as well,” Schumer wrote.