A few issues here. The first set of issues are factual, the others are historigraphical.

US entry. The US entered the war in April 1917. At this point in the war, both sides had made great progress in breaking "the riddle of the trenches." At Vimy Ridge, for example, the Canadian Corps (acting as part of a much bigger British Army) used a combination of advanced counter-battery techniques, rolling barrages, infantry organisation, and the like to break a well-fortified German position. They did it again in August 1917 at Hill 70. On the German side of things, Operation Michael in March 1918 made significant gains and introduced quite a bit of mobility back to the battlefield, but also inflicted very heavy losses on the attackers.

US performance. US entry was thus important, but not decisive. New US troops helped stem the spring offensives and reintroduced some confidence into the entente (and associated) powers, but did The great Allied counter-attack began at the Battle of Amiens in 1918 when the British Fourth Army smashed through something like 50+ German divisions in the span of a week. The Germans lost about 75 000 men, and never recovered. So while there are impressive American actions like Belleau Wood that rightly get commemrated, Americans often lose the forest for the trees when talking about the Great War generally. The AEF eventually numbered about two million - a very large army to be sure, but most AEF formations only came on line in the summer of 1918, when the decisive offensive was already well underway. The US lost 53 000 soldiers - less than the 60 000 of a much smaller country like Australia. France lost over 1.3 million soldiers in the war.

Russia. Russia dropped out of the war before US entry, so there is really no connection here at all.

Peace negotiations. To my knowledge, there were no viable peace negotiations going on in 1916. When a new British prime minister, Lloyd George came to power in December 1916 - five months before the US declaration of war - he was determined to fight it out.

And now the historigoraphy.

It's difficult, if not impossible, to ascribe events to individual people, especially as you get higher. Italian fascism took hold because Italians supported it. Black Friday happened for a number of very complicated reasons, from a wider cultural belief in the stock market to a number of ineffective market controls. Was Wilson linked with some of this stuff? Probably, but so were literally millions of other people.

Anyone who's ever been in school knows why it's so easy to dislike Woodrow Wilson. He is that one teacher. The one always lecturing, the one who doesn't come down of his high horse even for the sake of cleaning up after it, the one who truly believes that admitting when you are wrong is a lesson you should learn.

Now – personal preferences aside – I think that any suggestion that Wilson is to blame for Fascism is, frankly, complete nonsense. And actually crosses the line into that quite unfortunate habit of self-absolution, which is prominent in the public discourse on Italian Fascism, and, regardless of any warranted or unwarranted moral commentary, makes for extremely poor history.

To clarify, since my familiarity with Wilson stems almost entirely from Italian sources, and in that merely from the examination of the relations between the US and the Italian Delegations during the Peace Conference in Paris and subsequent months, where Wilson's personal involvement became nonetheless much more limited (both because of his return to the United States and because of his major health issues), I will only address the points which relate to the Italian matters and make no general evaluation of Wilson's presidential mandate, his career, legacy or personal history in the US.

Before moving on with that, I feel the need to observe that Wilson's personality (as well as his personal approach to diplomacy) – introductory jokes aside – appeared to become somewhat of an issue during his active engagement with the peace negotiations (which is to say, for the most part, from January to June 1919, even if Wilson's ideas for a post war settlement had been formulated ahead of most diplomatic engagements). The US President was extremely active and extremely involved with all sorts of diplomatic aspects, including a minute examination of borders and issues that might have been better left to the care of professional diplomats (which, incidentally, was a common criticism of Wilson at the time, and exactly one of the original reasons of the popular enthusiasm built around him). While his tendency to assume moralistic positions, and rely on those in order to dismiss or avoid more practical considerations, as well as his penchant for lecturing the other leaders of the Great Nations, didn't really seem to benefit his political aspirations in the long term. Furthermore – and one last note – Wilson's personal racist feelings, while usually left outside of the actual negotiations (by which I am not arguing that they didn't influence them, but merely that they were never an issue in his dealings with the Italian delegation), and regardless of the often instrumental contemporary criticism (which was far from the main focus of the Italian critics of the US President), did – in my opinion, at least, and from a more modern point of view – substantially undermine the positive elements of his political initiatives.

While these arguments against Wilson may be taken as legitimate, neither of the two played any role in the affirmation of Fascism in Italy.

 

Wilson – despite being “the most powerful man who ever lived” according to Italian Prime Minister V.E. Orlando, who was “desperately wrestling” with him during the “week of passion” (to use Aldrovandi-Marescotti's words) of April 1919 – had no remedy to offer for the weakness of the Italian institutions coming out of the war, for the extremely difficult state of Italy's finances (with national debt increasing about five times from 1914 to 1920), from the deep social tension which had increased during the war, rather than diminish as the “constitutional” interventionist forces had hoped. A situation that suffered from the critical inability of the Italian state to provide the masses with those forms of compensation, with that measure of satisfaction which had, by then, come to be recognized (by the masses themselves) as necessaries – and were therefore almost a precondition for a true participation of the Italian masses to the life of the nation.

The war, a long one instead of the brief “walk to Ljubljana” which the nationalist press had advertised, had cost Italy almost 600,000 dead and an even larger number of invalids. More so, it had substantially undermined the ability of the State – willing or not – to address the populace's demands (and their needs) and thus in good measure compromised the ability of the liberal system to promote a proper “democratization” through policies of popular consensus.

Even the ordinary routine of day to day political debate offers a dramatic (usually somewhat overly dramatic) picture of the social situation.

Enough said – argued the southern representative, Nicola Salomone, while listing a few examples in a parliamentary address from July 11^th 1919 – with the Ministry of Agriculture which has yet to produce certain silver medals awarded during the harvest of 1915 to a few women who took the place of their conscripted husbands. And that because, according to what they say, the late Minister Carcano didn't feel we could manage the expense. […]

And on July 10^th Genoese representative Luigi Edoardo Frisoni detailed the causes of an ongoing strike. According to him, the Government should have paid more attention to the situation of the two major lignite extraction facilities, in Spoleto and Castelnuovo, where production was currently halted, “due to a disagreement between workforce and ownership of the mines”. The crux of the matter was the worker's demand “for the continuation of the distribution of discounted rations for the families of those who had left the mining works in a non-definitive fashion […] and for the families of the deceased workers, as long as minor [for the purpose of employment – which means either less than 14 or 12 or 9 years of age, depending on what legislation Frisoni had in mind] children exist and the widow has not remarried”. The reply of the mobilization committee, as cited by Frisoni, went as follows:

“Any demand of economical character coming from the labor organizations assumes the existence of an employment contract with the industrial owner. One can't admit the existence of such a contract […] between an industrialist and those who used to work for him before they were called to arms. The latter are, after their dismissal, free to offer their service to any kind of industry or owner of their liking, and therefore one can't reasonably assume the existence between the two parts of any obligation productive of effects of any type. More so, and for the same reason, one can't assume the existence of any obligation between industrial owners and the heirs of deceased laborers”. […]

These are, of course, just two examples from the pile. For a broader examination of the intrinsic elements of weakness of the Italian liberal state, consider Vivarelli, R. - Il fallimento del liberalismo and Storia delle origini del Fascismo, especially vol. 2. - as well as Forsyth, D. - The Crisis of Liberal Italy

By which, I won't argue that unresolved social tension is the one and ultimate cause of Fascism – since one would already be hard press to stick to just a few relevant elements. Yet I think it helps to put certain arguments into a better perspective. And this is not just something of concern for the more popular political forces (both Frisoni and Salamone were land owners). The internal situation was a much larger concern, and already before the falling out between Wilson and the Italian Government, than any international trouble even for the liberal-conservative (and staunch interventionist) chief editor of the Corriere della Sera, Luigi Albertini. As he explained in a private letter to Orlando (April 10^th 1919), concerning the rumors (which had begun to be transpire on the Italian press) of the Italian delegation abandoning the Conference:

Those who envisage, for Italy and the world, the perspective of a triumph of our rights achieved by means of this petty blackmail – what are they thinking? Do they really believe that the country has nothing else in mind but Yugoslavs and Dalmatia? If the authors of those vehement lines could see what's the impact of their musty rhetorics on the public, they would water down their wine a lot. Nowadays the public opinion has much bigger concerns: they see the Bolshevik stain spread with vertiginous rapidity; they see the noise of revolutionary propaganda in Italy grow to an impassable volume; they take notice of some sort of bourgeois resignation, a form of passive wake, a fondness for novelty among those who have little to lose, of mistrust in the proper functioning of the ordinary restraints; they are forced to contemplate a general state of drunkenness in which the wildest vindications follow one another without any conciliatory sentiment being able to moderate them, to a gush of general madness which may come to pass without consequences, but which might also throw everything up in the air.