Yes the question is, is a U.S. strapping on it's six shooters sufficient to dissuade the Germans from unleashing the submarines? They were very worried about a U.S. intervention in the OTL, the reason they held off so long. So is a U.S. clearly gearing up for war enough to convince them not to chance it?
Depends what sort of USW.
Iirc as late as Dec 1916 the Army was only calling for USW against
armed ships. Wilson seems to have been coming round to accepting this, as he took no action over the sinking of the Marina and Arabia - both armed vessels - despite prodding from Secretary Lansing. However, he never stated publicly that he had changed his position in yhis way.
If Hughes were to make a speech declaring that "the murder of Americans on unarmed merchant ships is an act of war" - implying that armed ones were fair game, then Bethmann might have agreed to this form of USW at a time when H&L had not yet come out for the full-blown variety. This could have preserved American neutrality.
There is of course the consideration that the House of Morgan, the principal lender to Britain, had supported Hughes in the election. But for that very reason Hughes Might have been reluctant to back them - it could have looked like sordid deal, and Hughes was touchy about anything that called his good name into question.