Alford v. United States

At Alford's (defendant) mail-fraud trial, a former employee who testified against him was, at the time, being held in custody on separate felony charges; when Alford's counsel asked the witness where he lived — intending to surface his detention and explore whether it gave him a motive to curry favor by testifying favorably for the prosecution — the trial judge excluded the question as immaterial, reasoning a felony conviction might bear on credibility but mere pending detention would not.