William R. Day,
John Powers v. United States — Opinion of the Court
“ There is some difference of opinion expressed in the authorities, but the rule recognized in this court is that a defendant who voluntarily takes the stand in his own behalf, thereby waiving his privilege, may be subjected to a cross-examination concerning his statement. 'Assuming the position of a witness, he is entitled to all its rights and protection, and is subject to all its criticisms and burdens;' and may be fully cross-examined as to the testimony voluntarily given. ”
