The U.S. Commission on Civil Rights, frustrated by the Justice Department's failure to explain the dismissal of charges against New Black Panther Party members who disrupted a Philadelphia polling place during last year's elections, has subpoenaed the department demanding records showing how the case was handled. David P. Blackwood, the commission's general counsel, said Tuesday in a letter to the Justice Department that efforts since June to obtain an explanation had proceeded "without any success" and the "dearth of cooperation" had prompted the commission to issue subpoenas. "We are both mindful of the sensitivity of the subject matter involved and...