Tom Cotton is very far to the right; Gardner will have a tough time defending his Senate seat unless he has a sure chance at the Vice-Presidency. 2020 is likely to be a very rough year for Senate Republicans. Even with partisan fatigue, Americans will not want the harsh economic discipline of the gold standard, the elimination of Medicare and Social Security, and a combination of the elimination of the minimum wage and the substitution of a federal sales tax for the federal income tax. Cotton picks Joni Ernst to swing Iowa and that proves a blunder. She was going to lose her Senate seat. Her talk about castrating hogs makes her a one-trick pony. (Pardon the marginal mixed metaphor).
But even with a recession, Democrats do win Iowa, New Hampshire, and Virginia for the bare win of a nail-biter of an election. I'm tempted to believe that Hillary Clinton has selected the other Senator from Minnesota to be VP.
277: Clinton/Klobuchar(50.5%)
261: Cotton/Ernst(47.4%)
Others: 2.1%
This assumes that Tom Cotton does not try to use wars for profit as an appeal, in which case he gets derision as "Tom Cottonmouth", an allusion to a venomous snake common in Arkansas.