Which governor pardoned three convicted bombers in 1893 during the Haymarket riots, believing they were victims of the courts?

The correct answer is John Peter Altgeld. In 1893, he was the governor of Illinois and made the significant decision to pardon the three men who had been convicted for their involvement in the Haymarket riots of 1886. Altgeld believed that these defendants were victims of a biased judicial system and that their trials did not reflect fair legal proceedings. The context surrounding the Haymarket incident involved labor strikes advocating for workers' rights, and the outcome was heavily influenced by the social and political climate of the time, which was characterized by suspicion towards labor movements and immigrant workers.

By granting these pardons, Altgeld aimed to correct what he saw as a miscarriage of justice, highlighting the theme of governmental responsibility and compassion during a period of heightened tensions between labor and management in the United States. His actions also reflected his progressive views, as he sought to push against the prevailing attitudes of the day that favored strict law enforcement over the rights of workers.

The other options do not pertain to this event: Benjamin Harrison and Grover Cleveland were presidents without direct involvement in this case, and Theodore Roosevelt was not governor of Illinois during this period.