Collins, one of those who participated as a foot soldier in the rebellion, was captured after the crushing of the Easter Rebellion. However, he was released and began carrying out and played an important role in revitalizing the armed resistance. He pioneered urban guerrilla warfare.
He established a grassroots army of volunteers made up of young idealists and poor workers to fight for freedom. Others acted as an intelligence network that looked for information to expose British informers and spies, Irishmen who by working for the British were seen as traitors to the cause of national independence.
This basic formula of forming an informal army, acting in small effective and closely-knit teams, consisting of poor and marginalized idealists, most of them young, who then used violence, force, and fear to intimidate an overwhelmingly powerful and organized ruling government, has been copied by later rebel leaders and Marxist revolutionary thinkers, notably Che Guevara and Carlos Marighella.
Collins realized that attacking an organized force on the latter's own terms characterized by larger numbers and superior firepower would be futile. Having small forces attacking specific targets with impunity and relying on precise information would, and proved to be, more effective.
What resulted were years of brutal violence. However, instead of pressuring the British to capitulate, there would be an escalating spiral of death and conflict, leading to the formation and growth in size and power of what would later become the Irish Republican Army (IRA).
This background of violence, brutality, and revenge is the basis of the troubles that continue to wreck Northern Ireland and has served as the inspiration for terrorist groups that endanger the world to this day.
The film showed that while Collins deep in his heart was not in favor of brutal violence to achieve the noble end of freedom for which he fought, he found it the best way to catch attention and increase the popular support for their cause. In retaliation to the Irish's guerrilla tactics, every act was met with greater impunity by the British Army, which in turn had a legitimate reason of its own for suppressing an armed rebellion of what it believed to be a part of the United Kingdom.
Realizing that violence was not a long-term solution but was becoming part of a problem that was becoming bigger, Collins showed his willingness to compromise after the British agreed to allow the Irish to establish a political party that legitimately participated in the British parliament.
This strategy of legitimizing rebellious groups by making them participate in the democratic mainstream has likewise been used by nations to diffuse violence and allow due process to take its course. But it was short-lived, as the newly-elected Sinn Fein party representatives changed their minds and declared independence for Ireland, organizing the IRA to counteract British efforts to suppress the rebellion.
This turned out to be the cause of his downfall, because as his power within the independence movement grew, his comrades