I'm guessing the biggest difference is that Republicans started to realize he might lose. It's one thing to withhold your approval as a symbolic protest; it's different when you think the black Democrat might actually win.
As a Nebraskan, my answer to the soybean question would have been "Three to eight dollars per bowl, depending on which sushi restaurant you go to." It's not like it's something a whole bunch of people talk about. But, there is an expectation in ag states that their delegation members serve on ag committees, and Ernst does serve on the "Committee of Agriculture, Nutrition, and Forestry." Obviously, she doesn't pay that much attention. So, sort of a bullshit question, but did actually expose a legitimate issue. And what was great about Greenfield's answer isn't that she just demonstrated a knowledge of current pricing, but that she understood the term "break even pricing," which means she understands the dynamics on what it takes a farmer to survive financially. That's way more important in knowing what the price of corn is on October 15. I mean, she has a "D" behind her name, so it won't really matter much to those struggling farmers, but it was still impressive.