Italian...lets say enthusiasm, for the Triple Alliance was already souring in the years prior to the outbreak of war. Italy was already boosting relations with France and the UK since the turn of the century, most notably in a secret treaty signed in 1902 slating Libya for Italian annexation with French backing.

When the Italo-Turkish War for Libya broke out in 1911, Italy's Triple Alliance partners paradoxically refrained from supporting Italy's claim on Libya and instead suggested a mediated settlement with the Ottoman Empire regarding the status of Libya. The Entente however, fully supported Italy's declaration of war against the Ottomans and Italian annexation of Libya in accordance with the 1902 secret treaty.

The Triple Alliance's refusal to fully back their own ally's claim to Libya was still very fresh in the minds of Italians when WWI broke out, along with other outstanding Italian claims to Austro-Hungarian lands populated mainly by Italians, namely Trentino, Trieste, and Dalmatia. When war broke out in 1914 with an Austria-Hungary declaring war as the aggressor, Prime Minister Antionio Salandra declared that Italy would not commit its soldiers to the war in support of Austria-Hungary, citing the Triple Alliance as a defensive pact where Italy had no obligation to join an offensive war.

In the months following, Italian Prime Minister Salandra and Foreign Minister Sidney Sonnino began discussions with both the Entente and Central Powers over which side would reward Italy with the best deal for its intervention or continued neutrality. The Entente's territorial promises to Italy are outlined in the Treaty of London signed in April 1915, and was the deal that won over Italy. The Treaty of London promised Italy Trentino, South Tyrol, The Austrian Littoral, and Dalmatia in exchange for entry into the war against the Central Powers.

As for the Central Powers, talks for Italian entry into the war against the Entente did not take place. Instead, the talks regarded Austrian territorial compensation in exchange for Italy remaining neutral in the war. Austria offered Italy Trentino and parts of the Austrian Littoral, but Trieste and Dalmatia were not offered. The Italian delegation also demanded for French Tunisia to be transferred to Italy as soon as possible, where the Central Powers would only agree to this after the war was won. With the Entente offering clearly the better deal, talks with the Central Powers fell apart.

In the immediate leadup to Italy's declaration of war, Italian parliament under Giovanni Giolitti was very pro-neutral despite Italy's signing of the Treaty of London, this sparked a short political crisis were a pro-neutral Italian parliament would come into conflict with the King, who supported the Treaty of London. Prime Minister Salandra offered his resignation as Prime Minister in favor of Giovanni Giolitti on May 13, 1915. When Giolitti learned that the Treaty of London was already signed, he then declined to take up the position of Prime Minister and Salandra's resignation was rejected. On May 24 with the political crisis out of the way, Italy declared war on Austria Hungary.

To sum it up, The Italian government knew they were in a favorable position to receive concessions from either the Entente or Central Powers and weighed their options. Entering the war on the side of the Central Powers was not discussed, but instead Germany and Austria-Hungary attempted to give concessions in exchange for Italian neutrality in the war. Entente promises of territory Italy long coveted at the expense of Austria-Hungary won out even against a largely pro-neutral Italian parliament.

For further reading, definitely check out Modern Italy: A Political History by Denis Mack Smith where he gets down and dirty with the political squabbling Italian politicians went through in the months of neutrality leading up to WWI.

As obvious as it may sound, not enough.

Italy was in the Triple Alliance at the start of the Great War, and the progressive revision of her diplomatic position – or to use a less charitable and a bit too simplistic wording, her “switching sides” - during the early months of the conflict was in large measure a result of the fact that the alliance with Austria-Hungary appeared no longer coherent with its long term purpose – or, again, less charitably, no longer advantageous.

The distinction, rather than exculpatory, is one that I regard as quite substantial, as the maintenance of good relations between Italy and Austria – while not, after over thirty years of peaceful coexistence and at times of collaboration – had always been predicated on an exchange of interests. It was not, in other words, a marriage of love, but one driven by political and international conveniences.

For Italy especially, 1882 – the year when the Triple Alliance had been subscribed for the first time – had seen the aftermath of the “slap of Tunis” and a substantial deterioration of her relations with France, resulting in a desperate commercial war during the late 1880s and in episodes of institutional panic (Prime Minister Francesco Crispi had infamously jumped the gun on reports of the French fleet leaving Toulon – to be fair, that was the France of Georges Boulanger, so that concerns were not entirely unwarranted). Anyways, this meant that Italy was open to (and very much needed) a substantial rapprochement with Germany, which had entered an alliance with Austria-Hungary in 1879. Consequently, the establishment of a modus vivendi with Austria-Hungary – the mortal enemy of the Italian nation, and main obstacle against the Italian unification for over half a century – was also necessary.

With time, and the collapse of Crispi's attempts to turn the Triple into an anti-French front, the rationale of Italy's alliance with Austria-Hungary had evolved into the more moderate convenience of a conservative block invested in the maintenance of a balance of power, with especial attention for the initiatives of France and Russia. An Alliance whose defensive character was unquestioned and clearly stipulated – and this exactly because its defensive character was its main, essential purpose.

On the positive side, good neighborhood relations favored internal stability (which both Italy and Austria-Hungary were frequently lacking), improved the relations between Italy and the Holy See (as Austria-Hungary had maintained her traditional ties with the Pontifical State), prevented troubles in the Adriatic Sea and allowed the Italian treasury some respite from the expenditure escalation that a state of tension with a less cautious naval power implied. On the negative, it comported for Italy the abandonment of her traditional irredentist policies, favoring instead an agreement with the Austrian authorities to ensure a good treatment of the Italian minorities. It also required stability in the border region, as the whole coexistence building was founded on the possibility to find a “diplomatic” solution to any arising element of tension.

In this context, the German action had been, since the last years of Bismark's government, directed at providing Italy and Austria-Hungary with a “compensation chamber”, a safe space to sort their issues. Which, as the usual saying goes, involved the Balkans. A place where stability appeared a scarce commodity. This was the context of art. VII of the Triple Alliance – in the amended version of 1912.

Austria-Hungary and Italy, having in mind only the maintenance, so far as possible, of the territorial status quo in the Orient, engage to use their influence to forestall any territorial modification which might be injurious to one or the other of the Powers signatory to the present Treaty.

To this end, they shall communicate to one another all information of a nature to enlighten each other mutually concerning their own dispositions, as well as those of other Powers. However, if, in the course of events, the maintenance of the status quo in the regions of the Balkans or of the Ottoman coasts and islands in the Adriatic and in the Aegean Sea should become impossible, and if, whether in consequence of the action of a third Power or otherwise, Austria-Hungary or Italy should find themselves under the necessity of modifying it by a temporary or permanent occupation on their part, this occupation shall take place only after a previous agreement between the two Powers, based upon the principle of a reciprocal compensation for every advantage, territorial or other, which each of them might obtain beyond the present status quo, and giving satisfaction to the interests and well founded claims of the two Parties.

 

I don't wish to suggest with this that the relations between Italy and Austria-Hungary were of a purely instrumental nature and that no concept of maintaining a proper conduct existed between the two nations – even if on both sides there were less than becoming episodes (the Italians had not forgotten the intitiative of the Austrian High Command, attributed to gen. Conrad, but likely from some subordinate, to examine the plan of a preemptive strike after the earthquake of Messina had killed 80,000). More so accounting for the fact that the ability of sorting out those issues, which had been once source of fundamental divide between the two neighboring states, had come to represent a point of pride for many of the exponents of the two diplomatic worlds.

In general terms, and despite varying interpretations, at the time of the assassination of the Archduke Franz Ferdinand, the relations between Italy and Austria-Hungary were good – good enough at least. To cite the informal remarks of the Italian Minister of Foreign Affairs, the Marquis of San Giuliano (second week of July 1914)

The relations between Austria and us have improved during these last times; there is, if not more trust, less mistrust. This improvement is something I had set as my objective, when I had taken charge at a moment when our relations were especially tense.

San Giuliano had assumed office in 1910, during the build up to the crisis of Agadir, after the Austrian annexation of Bosnia-Herzegovina in 1908 and before the Italian war against the Ottoman Empire which had earned Italy the possession of Libya and of the Greek archipelago of Dodecanese. And then again, before the temporary definition of the Albanian question during the Conference of London in 1912-13.

As you can see, speaking of stability per se would be somewhat of an exaggeration; it is also true nonetheless that, as long as both powers agreed on the importance of maintaining their relations, a manner of accommodation appeared to exist.

In a certain way, the Austrian decision to take the most energetic approach to the Serbian matters – and insist on the exact execution of their ultimatum, despite the Italians sharing informally their concerns – represented for the Italian diplomatic world a confirmation that Austria-Hungary was putting the solution of her internal troubles ahead of her relations with Italy. This inspired almost immediately a general disillusionment on the Austrian willingness to provide those “reciprocal compensations” that the Triple Alliance gave Italy the right to demand. Furthermore, the secrecy of the negotiations between Austria and Germany during the preparations of the Austrian intervention, culminating in the announcement, without consultation, of the Austrian declaration of war – while motivated by obvious reasons – did little to dispel this impression.

As a result, the general outlook of the Italian establishment was that Austria-Hungary was relying on German support to settle their issues in the most affirmative fashion, and banking on the Italian weakness and inadequate military preparation to make it so that Italy would remain neutral anyways.