MIDTERMS: Could The Tight Arizona Senate Race Foreshadow A Red Wave?

Politico and the Cook Political Report have both moved their ratings of the Arizona Senate race between incumbent Democrat Senator Mark Kelly (D-AZ) Republican candidate Blake Masters from "lean-Democrat" to "tossup."

• The move illustrates how significantly the political environment has swung towards the GOP in October. In August, Kelly had an 11% aggregated polling advantage over Masters, according to FiveThirtyEight.
• Politico: “Blake Masters [...] had been left for dead in some quarters. Even Masters’ own tech billionaire benefactor, Peter Thiel, seemed on the cusp of abandoning him. But in mid-October, Thiel reportedly committed to spending another $5 million on his Arizona protégé.”
• Masters’ recovery in a race which should strongly favour Kelly, as a broadly popular incumbent in a state which has recently trended Democrat, hints at the possibility of a “red wave” in the Senate.
• In a "red wave" scenario, the GOP holds tossup Pennsylvania, Wisconsin, North Carolina, and Ohio and flips Arizona, Nevada, Georgia, and New Hampshire.
• Such a scenario, which appeared impossible just a few weeks ago, would give the GOP 54 Senate seats and decisive control of the upper chamber.