You have to pick just one. This is obviously unreasonable, but I'm cornering you and asking:
"Which of the following factors do you think was most significant in the Democratic victories in this US midterm election?"
(I'm also not asking what mattered most to YOU but what you think "swayed the public most")
@futurebird of course options #2 and #3 were why #1 was a problem, but I don't think very many Americans have that level of sophisticated decision making.