His success managing the Republican National Convention drew national attention, and in 1967 he was made coordinator of federal law enforcement. Under Warren Christopher, who was the deputy attorney general, he managed the Federal Command Post at the Conrad Hilton hotel overlooking Grant Park in Chicago during the 1968 Democratic Convention. Mayor Richard Daley had requested federal back-up after numerous threats by protesters. After assessing the situation, Pomeroy was frustrated with Mayor Daley's approaches, especially putting officers on 12-hour shifts, as well as being informed that he had no jurisdiction over the Chicago police force. He did have control over the Illinois National Guard and ordered them to replace the Chicago Police Department at various times, including one night in front of the Hilton hotel. Pomeroy is credited to have, despite Mayor Daley's interference, kept the situation from becoming worse than it could have been.