Quinnipiac polls have produced some of the best numbers for Democratic candidates across the country this year, and earlier this month the pollster found Iowa Republican senator Joni Ernst trailing Democrat Theresa Greenfield 45 percent to 50 percent. But the latest Quinnipiac survey, conducted October 23–27, shows Ernst turning things around: She now holds a slim lead — 48 percent to 46 percent — over Greenfield. The same poll shows Trump one point ahead of Biden: 47 percent to 46 percent.
At the moment, Greenfield is ahead of Ernst by 1.5 points in the RealClearPolitics polling average, but it’s not unusual for a Senate candidate trailing by less than 3 points in the RCP polling average on Election Day to win.
In Iowa, Republicans have outperformed their poll numbers in the last three election cycles: “In 2014, Ernst led her Democratic opponent by 2.3 points in the RealClearPolitics polling average; she won by 8.5 points. In 2016, Trump led Clinton by 3 points in the RCP average of Iowa polls; he beat her there by 9.4 points. In 2018, GOP governor Kim Reynolds trailed by 0.7 points in the final average of polls; she won by three points.”