There was disagreement among labor unions at this time about when a holiday celebrating workers should be, with some advocating for continued emphasis of the September march-and-picnic date while others sought the designation of the more politically-charged date of May 1. Conservative Democratic President Grover Cleveland was one of those concerned that a labor holiday on May 1 would tend to become a commemoration of the Haymarket Affair and would strengthen socialist and anarchist movements that backed the May 1 commemoration around the globe.[10] In 1887, he publicly supported the September Labor Day holiday as a less inflammatory alternative.[11] The date was formally adopted as a United States federal holiday in 1894.[citation needed]