Yes, of course Hughes would have asked for (and gotten) a declaration of war, and would actually suffer a bit less from it politically than Wilson did--because Hughes could blame Wilson for making war necessary ("if we had just shown more firmness, if we had been more prepared" etc.) Hughes was after all the candidate of the more hawkish party, the party of TR and Root and Lodge. And even during the campaign, when he was appealing for German-American votes, all he did was to say that he would act firmly against violations of American rights from
either side. Indeed, he said he would have broken off diplomatic relations with Germany after the
Lusitania incident (while of course adding that the ship would never have been sunk if the Germans had believed what Wilson had said about "strict accountability.")
https://books.google.com/books?id=Pk_WCgAAQBAJ&pg=PA112
BTW, what makes you think America was
not divided over the War in OTL? Certainly the elections of 1917, with big gains by Socialists, would seem to indicate that acceptance of the war was far from unanimous.