This is the least surprising result to people who have actually been paying attention. It's only this site where you see "IA is now MO" or "IA R+15" takes. Yes, Trump may still be a slight favorite here. No, the margin won't even come close to last time. Not sure how many times some of us in the midwest have to repeat how uniquely toxic HRC is here and how that fact alone had an impact on results in 2016.
Ernst should be worried. With Greenfield pulling 10% of Trump supporters it's no longer unlikely that he carries Iowa and she loses.
This poll does not surprise me particularly, as someone who has lived in the Midwest (Ohio) and spent time throughout the region over the decades.
Trump only captured 51.2% of the vote in '16, which although higher than Romney / McCain numbers (46/44%), against a Midwest Democrat Obama, wasn't really much higher than Bush Jr '04 / '00 (49.9% / 48.2% respectively).
Hell, I remember watching the '88 GE Election at the local small County DEM HQ and cheering when Iowa was called almost right away for Dukakis...
Sure it does not appear that Biden is performing quite as well as Obama in parts of the Midwest in 2012 (Based upon current polling), but overall appears to be close to matching...
It might not be quite enough to flip OH & IA, but definitely worthy of a Biden investment, plus media markets "bleed-over" in this part of the Country....