Beyond his age, Arpaio lost his Maricopa County sheriff’s race in 2016 by double digits to a Democrat, in a Republican stronghold that accounts for around 60 percent of the votes cast in the state. And yet one recent poll put Arpaio neck and neck with McSally, and ahead of Ward. He has national fundraising prowess, off-the-charts name recognition and an innate understanding of the Republican base. He’s tight with Trump. His campaign message—I’m a martyr of the Obama administration’s Justice Department—threatens to resonate deeply with Republican primary voters. If the White House continues discussing amnesty for Dreamers, “the right will look for rallying points,” a source familiar with Donald Trump’s thinking told me. “And one will be Sheriff Joe.”

The hope inside the McSally campaign and among her establishment backers is that Arpaio paves the way for her to win in the August primary by splitting the Tea Party vote with Ward. Be careful what you wish for, Marchant suggested. “There are McSally people cheering this on, but it’s dangerous,” Marchant said. “There’s a real sense he could win the primary and ‘Roy Moore’ us.”

That could make Arpaio’s Senate run a painfully selfish decision at a time when demographic changes in Arizona have made the state increasingly competitive. But just like the coda of Favre’s career suggests—he took the Minnesota Vikings to the brink of a Super Bowl only to blow it with a foolish interception—there is no graceful way to push out a legend.