Brief for appellants and joint appendix, United States Court of Appeals for District of Columbia circuit, no. 10245, Tom C. Clark, attorney general, and Watson B. Miller, commissioner of immigration and naturalization, v. Irving Potash; no. 10246, Tom C. Clark, et al., v. John Williamson; no. 10247, [same] v. Ferdinand C. Smith; no. 10248, [same] v. Charles A. Doyle, appeal from United States District Court for District of Columbia.