As States sent Union regiments south, on April 19, Baltimore mobs in control of the rail links attacked Union troops who were changing trains. Local leaders' groups later burned critical rail bridges to the capital and the Army responded by arresting local Maryland officials. Lincoln suspended the writ of "habeas corpus" where needed for the security of troops trying to reach Washington. John Merryman, one Maryland official hindering the U.S. troop movements, petitioned Supreme Court Chief Justice Roger B. Taney to issue a writ of "habeas corpus." In June Taney, ruling only for the lower circuit court in ex parte Merryman, issued the writ which he felt could only be suspended by Congress. Lincoln persisted with the policy of suspension in select areas.