The preliminary question is whether without World War I Wilson would have won a second term. Admittedly, the question of whether the War helped or harmed him in 1916 is a complex one. OT1H, there was "he kept us out of war" and the fear that the Republicans (because of the influence of people like TR and Root) would get the US into the War (ironically, at the same time the Democrats argued this, they also portrayed Hughes as pro-German). OTOH, despite the temporary improvement in US-German relations in 1916, many German- and Irish-Americans still resented what they considered Wilson's partiality toward the Entente. But in any event, after an initial panic, the War did produce a temporary prosperity in the US that made people forget about the recession of 1913-14 (the Republicans predictably blamed the recession on the Underwood Tariff and Wilson's "anti-business" policies). So it is no means certain Wilson would have won a second term without the War. But even if he did, I just do not see him winning a third one. Even TR had to pay lip service to the idea that a president should not serve a third consecutive term. (Besides, after eight years in office, there is some wear and tear in almost any administration.)
