One of the key factors of the revolutionarys failures was due to the repeated involvement by Austria and its imposing army, who were a major force in Europe and the world at the time. Led by Metternich, the Austrians quashed revolution after revolution. For example, in 1821, where King Ferdinand had granted his state, Naples, a constitution out of fear, he appealed to Metternich for help, who duly obliged as he opposed the revolutionaries because they disturbed the peace in the whole region.
Therefore, in March 1821, Austrian troops marched into Naples and easily overran the rebel forces with a superior army in strength, training and weaponry. This made it almost impossible for any revolutionary group, whether united or separate, to outmatch the Austrians, whose military strength was far greater than the revolutionaries. This also occurred in 1848, when Charles Albert, revolutionary king of the most powerful state, Piedmont was twice devastated by the Austrians. First, in June, he was defeated in Custoza and forced to sign an armistice withdrawing from Lombardy and again in March 1849 where he was heavily defeated in Novaro.
This was a theme throughout the entire time period of 1820-49, with Metternich crushing revolutions in Piedmont, Lombardy and Sicily among others, with this trend only declining when revolutions arose in Vienna, forcing Metternich to focus on events closer to home. Therefore Austrian military might was an overwhelmingly strong factor in the failure of every revolution in this time period. Another reason for the failures was a distinct lack of unity in almost all of the revolution, with the groups from different states and areas refusing to cooperate with each other as they were in the main more concerned with local affairs than the bigger picture of a united Italy.
For example, in 1832, Modena appealed for help from the revolutionary government of Bologna for no particular reason other than they didnt want to communicate or cooperate with one another. Another example is the Sicilian revolutions. They started a revolution in their capital city of Palermo and had soon ousted the previous regime to replace it with a revolutionary provisional government.
However, when revolutions spread to the mainland of Naples a few days later, they had no plans of assisting them; instead making their policies clear by breaking away from Naples and becoming an independent state. Instead of national or regional unity, they instead, from the entire period of 1820-1848, wanted a free and sovereign country of their own. The fact that the different groups didnt cooperate with one another, and in some cases, such as this, had entirely dissimilar aims for having a revolution, meant that they could easily be overridden one by one because individually they were very weak.
A lack of outside help from other countries that were meant to be enemies with Austria did not help the revolutionaries cause. At the beginning of the revolutions in 1820, fresh off the back of the establishment of the new republic in France after the French revolutions, there was the hope that they would support the Italian revolutionaries in overthrowing their reactionary rulers, just as the French had done to their own monarchs less than 30 years before.
In 1831 as well, despite appeals for French help, their pleas were ignored and Austria swept the isolated revolutions aside. In fact, instead of assisting the revolutionaries, in 1848 they instead intervened seemingly on the other side of the revolutions in order to assist the Pope, but in doing so they overpowered the Roman Republic, a revolutionary area headed by Giuseppe Mazzini. The French military brought hardship upon the people of the Rome after defeating Mazzini, seemingly in a hypocritical way as they themselves had fought to rid themselves of an iron grip previously but were instead now the iron grip rulers.
On the Popes return, the repressive regime present before the Roman Republic returned. This shows that the French were far more against the revolutions than for them. They wouldve been the natural protector of the revolutions due to their recent history and their hatred of Austria, but it wasnt to be and this was a key reason in why the uprisings ultimately all failed. Despite these reasons, the lack of popular support was no doubt a contributing factor into the revolutions failure. The fact that in most states, around 90% of the population were peasants, but were not included in any decisions or contributed to the fighting effort meant that there was never likely to be popular support, because peasants views were not heard so their living conditions wouldnt necessarily change no matter who was in charge.
They would most likely have very little idea of what was even happening in their state. For example, in 1831 the peasants were deliberately excluded from taking part in any form of the revolutions, except for in Sicily where peasants were involved. This was due to the fact that the middle class professionals believed that the poorly educated peasants would end up being detrimental to the cause and would spark their own revolution fighting for their rights and eventually leading to the rule of the mob.
Overall, there were several key factors in the failure of the revolutions between 1820 and 1849, such as the might of Austria, the distinct lack of unity between revolutionary divisions and the lack of allies from the international community.
Despite the importance of these factors, the lack of popular support cannot be ignored as a factor, but the middle classes had a steadfast fear that if they permitted peasant help, they would turn the cause into riots. This was seen in Sicily where peasant assistance was encouraged, but ended in the masses destroying property, freeing prisoners and burning tax collection papers, as they had the sole intention of causing anarchy. Therefore, the lack of popular support was not a crucial factor but merely a side point in the revolutions failures.