IIRC, Wisconsin at least was a staunchly Republican state of the era.
So was Minnesota, but that didn't stop Hughes coming within 392 votes of losing it in 1916. Had he done so, of course, we would never hear of the famous late returns from CA, as Wilson would be home and dry without them.
I accept your point that the backlash against Hughes might not be as severe as OTL's against Wilson - but his problem is that it doesn't need to be. Apart from CA, there were three more states - MN, IN and WV - which Hughes took by a single percentage point or less. Had he lost them, he'd have been left with only 221 votes to Wilson's 310. Even the smallest slippage from his 1916 performance will tip him out of the White House - and if Americans have had to put up with those "meatless days" and what have you, they are going to be thoroughly brassed off, so it won't be just a tiny shift
But anyways, who's to say President Hughes is as harsh on Germany as Wilson was IOTL?
Then he'll be criticised for letting them off too lightly. The ToV was a "no win" situation for its authors. They'd be seen as wrong whatever they did. It is no accident that all the "Big Three", not just Wilson, vanished from the scene within a few years of its signing. Nothing positive was ever going to come out of that shambles.
It should also be stated that between the two elections, there was an increase in voting size by about eight million voters with the passage of women's suffrage.
Would it still have passed under Hughes? He would have supported it, but would he (or any Republican) have been able to procure as many Southern votes and ratifications as Wilson did? I may be wrong, but I suspect you need a Democratic POTUS to get the 19A through.
And after the hardships of the war, would women voters be any less eager for a change than male ones?
I say all this with regret. I don't know if anyone here remembers my old magnum opus, "Mr Hughes Goes To War", but anyone who does will realise that Charles Evans Hughes is one of my favourite figures from the era in question. That said, however, the more I've learned about him, the more I feel that the Supreme Court was his natural home, and that he made an error in leaving it to run for POTUS. With the best will in the world, I can't see him as a two-term President, and I doubt if his single term would be a happy one.