In the first-ever poll of Iowa's Senate race, conducted a week after former Lt. Gov. Patty Judge won the Democratic primary, PPP finds veteran GOP Sen. Chuck Grassley leading her by a less-than-dominant 48-41 margin. While we don't have any other data to directly compare these numbers to this cycle, we can take a look at Grassley's very long electoral history, and in that light, 48 percent doesn't look particularly good. In 2010, Grassley consistently polled in the 50s and even low 60s en route to a 64-34 romp. And while we don't have polling data handy from prior years, Grassley's prior re-election wins saw him take 66, 70, 68, and 70 percent of the vote, stretching from 1986 through 2004. (He really has been in office forever.)
So while a 48-41 lead might look relative comfortable for other incumbents, to see Grassley under 50 is notable. (The only poll that had him under 50 in 2010 was from the discredited firm Research 2000—and in any event, it was contemporaneous with a PPP survey that put him at 57.) All that said, though, Judge still has some massive hurdles to overcome in order to unseat the incumbent. Despite the hits he's taken for months for leading the Republican blockade of the Supreme Court as chair of the Judiciary Committee, Grassley's job approval rating is still above water at 48-41. (Judge's favorables are 34-42.) And Grassley has a long reputation as a champion for his state that even his recent elevation as commander of the GOP's partisan shock troops can't completely erase.
He also has a lot more money than Judge, and so far, the big outside groups haven't signaled a major interest in getting involved in Iowa. But there's another positive for Judge in PPP's poll (which was conducted on behalf of the liberal Constitutional Responsibility Project): Hillary Clinton leads Donald Trump 44-41—and Trump's favorables are a terrifying 33-64, while Clinton's look downright lovely by comparison at 42-55. Barack Obama carried Iowa by 6 points in 2012, and it certainly looks like the undecideds here should favor Clinton. Grassley's always managed to win an unusual amount of crossover voters, but can he keep that magic going in this day and age? That will be his challenge.