Some points to consider:
There are a number of brilliant scenes in the film that help capture not only the battle between ideals and weakness, but also the immorality Gypo feels for being an Informer.
One) The blind man. If justice is blind then the Gypo is sentenced to death from the moment he walks out of the police station. Upon seeing the blind man, Gypo intends to make yet another sacrifice of his morality to save his own skin, but when he realizes the man is blind gypo gives the man a quid and goes on way.
Two) The camera consistently shifts to clocks after Gypo has taken the reward money. Literally he’s running out of time. While Gypo might race from one section of Dublin to the next, his movements are followed and soon everyone will see his shame.
Three) The court scene. The nature of the party’s court is underground and secret. Not only does this court convene at 1:00 am, the justice being doled out is not in a proper courtroom of elected officials, but in the courtroom of the ordinary people.
Finally, the constant focus on the money. Whether it is the from the beginning of the film and the reference to Judas or the way the camera follows the bills and change Gypo carries, Ford wants the viewer to realize that principles aren’t free. Money is precious in this Ireland, even coins, the viewer can understand why Gypo goes after the reward money. He wants out of this dark world, he wants his girl to be respectable, he wants to start a new life. And perhaps, it is through the focus on money that Ford highlights one of the key aspects of film: The corruption of the American Dream.
While The Informer is not set in America, the American dream is very much present in this film. The reason behind Gypo’s deceit is the desire to go to America. For Gypo and Katie, America promises freedom from oppression, freedom from strife, and most importantly, freedom from their past. But similar to black Americans who arrived on America’s shores via slave ship’s and then upon winning their freedom from slavery are weighted down by Jim Crow in the South and ghettoizing in the North, America’s promise of freedom is not available to all who desire it.
In fact, without even stepping onto American soil, Gypo and Katie learn an essential fact of American life, that money is the root of all evil.