“ Alabama, supra, applied. The Court of Appeals disagreed, saying that arraignment in Alabama is 'a critical stage in a criminal proceeding' where rights are preserved or lost (368 U.S. 53-54, 82 S.Ct. 158) , while under Maryland law there was 'no requirement (nor any practical possibility under our present criminal procedure) to appoint counsel' for petitioner at the preliminary hearing * * * nor was it necessary for appellant to enter a plea at that time.' 227 Md., at 625, 177 A.2d, at 882. ”