Bresci inspired some anarchists to carry out their own acts of propaganda by deed, most prominently Leon Czolgosz's assassination of United States president William McKinley.

[5] On 3 October 1892, Bresci and a group of about twenty anarchists confronted two police officers that had given a young worker a citation for not closing his butcher shop on time.

[24] Protests in Milan against the rising price of bread, in which men, women and children participated,[25] had been violently suppressed by the Royal Italian Army, which fired on and killed many of the protestors.

[26] Bresci swore revenge against the king, Umberto I of Italy, who he held personally responsible for the massacre,[27] as he had decreed a state of siege in Milan and awarded Fiorenzo Bava Beccaris, the general who ordered the shooting.

He spent most of the day walking around town and eating ice cream, briefly stopping for lunch with a stranger, whom he told, "Look at me carefully, because you will perhaps remember me for the rest of your life.

[43] Bresci had positioned himself along the road exiting the stadium to give himself a chance at escape;[42] the excited crowd swept him within three meters of the king's car and blocked his way out.

[48] His lawyer, Francesco Saverio Merlino,[49] argued that the idolization of kings had weakened Italy and that the criminalization of the anarchist movement had directly led to Umberto's assassination.

He proposed that the decriminalization of radical ideologies and the resumption of civil liberties would put an end to propaganda of the deed, the anarchist practice of political assassination.

[55] Another popular conspiracy theory asserted that Giuseppe Ciancabilla had originally been selected as the assassin by a revolutionary committee in London but was replaced by Bresci after he got into a conflict with Malatesta over the editorship of La Questione Sociale.

[58] The Italian diplomats Giovanni Branchi [it] and Saverio Fava were themselves left thoroughly dissatisfied with the "worthless" investigations conducted by the New York City Police Department, United States Secret Service, and the Pinkerton detective agency.

His daily rations consisted largely of soup and bread, with meat being saved for Sundays and public holidays, and occasional wine and cheese bought with money sent by his wife.

[74] Upon receiving word of Bresci's death, Giolitti immediately dispatched a prison inspector to Santo Stefano, where he reportedly arrived late on the night of 22 May.

[75] The New York Times celebrated the news of Bresci's death,[48] while Umberto's successor and son, Victor Emmanuel III, commented that it was "perhaps the best thing that could have happened to the unhappy man".

[77] Investigations into Giolitti's papers in the Central Archives of the State found two empty folders pertaining to Bresci, the title of the first indicated that the prison inspector had actually arrived on the island on 18 May 1901.

[79] Subsequent governments led by Giolitti passed a series of reforms of the Italian law enforcement apparatus, reining in police repression against striking workers.

[80] Giolitti himself downplayed or suppressed information about further violent attacks by anarchists, even omitting any mention of anarchism from his memoirs about Bresci's assassination, which he depicted as the result of a "deranged mind".

[82] Robert Gascoyne-Cecil, 3rd Marquess of Salisbury, the then British prime minister, responded to the assassination by proclaiming that European governments had been too lenient towards anarchists, whose "morbid thirst for notoriety" he feared presented a threat to the existence of civilization.

[85] Bresci's assassination of Umberto nevertheless contributed to a rising climate of xenophobia and anti-anarchist sentiment in the United States, culminating in the passage of the Immigration Act of 1903.

In its ode to Bresci, the paper described him as a "kind hearted and humane man" who had resolved to kill the "tyran[t]" Umberto, not as a representative of an organization but in an individual act of revenge for the "great suffering and misery caused by the oppressive measures of the Italian government".

[90] Bresci was praised in the same paper by Emma Goldman, who said he had "loved his kind, felt the existing wrongs in the world, and dared to strike a blow at organized authority".

[91] She described him as having had "overflowing sympathy with human suffering",[92] and declared his assassination of Umberto to have been "good and noble, grand and useful", as she believed he had intended it to help "free mankind from tyranny".

[97] Although Bresci's wife did not know about her husband's plan to assassinate Umberto, or even what anarchism entailed, she was routinely surveilled by the police and harassed by members of her own community, forcing her to move to Chicago.

[98] When the Italian monarchist newspaper L'Araldo Italiano raised one thousand dollars to decorate Umberto's tomb,[88] the Paterson anarchists quickly matched the amount to support Bresci's widow and two daughters,[99] despite police harassment at their fundraising events.

[101] A Roman Catholic priest was imprisoned for declaring his support for Bresci's actions, which he characterized as "an instrument of divine vengeance against a dynasty [the House of Savoy] that had deprived the Popes of their temporal power.

[103] Shortly after Umberto's death, the French anarchist François Salson attempted to assassinate the Persian king Mozaffar ad-Din Shah Qajar in Paris.

Although Salson himself never disclosed his motives, international newspapers (including Corriere della Sera, The Times, and the New York Herald) all claimed that the attempt had been directly inspired by Bresci's actions.

[90] In the wake of this assassination, mounting public pressure and police surveillance forced Bresci's family to flee their home in Cliffside Park, New Jersey.

[110] In 1911, Italian anarchists inspired by Bresci planned to assassinate Victor Emanuele III and Giolitti at the Turin International but were arrested before they could carry out their attack.

[121] In July 1986, the Italian Communist Party-controlled municipal council voted to allow the anarchists space in the Turigliano cemetery [it] to construct their monument to Bresci to the protest of monarchist activists and the then interior minister Oscar Luigi Scalfaro.