If I were a republican, which is, understandably, impossible, I would be very nervous about millions of 18 year-olds about to vote for the first time. I predict that these young voters will be highly motivated to go to the polls, and I believe it is unlikely that they will be casting many red votes. I would also be nervous about female voters:

If women voters who oppose President Trump turn out in large numbers, they can provide the key to electing a Democratic-controlled House and Senate. Ronald Brownstein has noted that 62% of college-educated women are planning to vote for Democrats in November. According to an NBC News/Wall Street poll, the president's favorability rating among college-educated white women has fallen from 32% to 27%. And the Republicans only receive positive marks from 23% of this pool. In the special elections in Virginia, Alabama, and Pennsylvania, the Republicans performed poorly with women voters.
And the president's numbers have also fallen among blue-collar white women who were important to his victory last November. In RealClear Politics, David Brady and Brett Parker recently recounted how weak the enthusiasm is for his presidency among female voters, and the widening gender gap between the parties.

So, ironically, the orange emperor HAS united Americans. Indeed, he has united the very Americans who will make America great again.