Harlem and three dead anarchists. The New York City Police Department inaugurated its bomb squad within a month. Bomb plots continued throughout the rest of the year. Although the UMWA failed to win recognition from the company, the strike had a lasting effect both on conditions at the Colorado mines and on labor relations nationally. John D. Rockefeller Jr. engaged W. L. Mackenzie King, a labor relations expert and future Canadian Prime Minister, to help him develop reforms for the mines and towns. Improvements included paved roads and recreational facilities, as well as worker representation on committees dealing with working conditions, safety, health, and recreation. He prohibited discrimination against workers who had belonged to unions and ordered the establishment of a company union. The miners voted to accept the Rockefeller plan. Rockefeller Jr. also brought in pioneer public relations expert Ivy Lee, who warned that the Rockefellers were losing public support and developed a strategy that Rockefeller followed to repair it. Rockefeller had to overcome his shyness, go to Colorado to meet the miners and their families, inspect the homes and the factories, attend social events, and listen closely to the grievances. This was novel advice, and attracted widespread media attention. The Rockefellers were able both to resolve the conflict, and present a more humanized versions of their leaders. Over time, Ludlow has assumed "a striking centrality in the interpretation of the nation's history developed by several of the most important left-leaning thinkers of the 20th century." Historian Howard Zinn, noted for his controversial reframing of U.S. history, wrote his master's thesis and several book chapters on Ludlow. George McGovern wrote his doctoral dissertation on the subject. In 1972, the same year as his U.S. presidential campaign, he published this dissertation with the help of historian Leonard Guttridge under the title The Great Coalfield War. A United States Commission on Industrial Relations (CIR), headed by labor lawyer Frank Walsh, conducted hearings in Washington, DC, collecting information and taking testimony from all the principals, including Rockefeller Sr., who testified that, even after knowing that guards in his pay had committed atrocities against the strikers, he "would have taken no action" to prevent his hirelings from attacking them. The commission's report endorsed many of the reforms the unions sought, and provided support for bills establishing a national eight-hour workday and a ban on child labor. The last survivor of the Ludlow Massacre,