The provision requires, of course, that the defendant be afforded legal process to compel witnesses to appear, 186
but another apparent purpose of the provision was to make inapplicable in federal trials the common-law rule that in cases of treason or felony the accused was not allowed to introduce witnesses in his defense. 187
''The right to offer the testimony of witnesses, and to compel their attendance, if necessary, is in plain terms the right to present a defense, the right to present the defendant's version of the facts as well as the prosecution's to the jury so it may decide where the truth lies. Just as an accused has the right to confront the prosecution's witnesses for the purpose of challenging their testimony, he has the right to present his own witnesses to establish a defense. This right is a fundamental element of due process of law,'' applicable to states by way of the Fourteenth Amendment
, and the right is violated by a state law providing that coparticipants in the same crime could not testify for one another. 188
The right to present witnesses is not absolute, however; a court may refuse to allow a defense witness to testify when the court finds that defendant's counsel willfully failed to identify the witness in a pretrial discovery request and thereby attempted to gain a tactical advantage. 189
In Pennsylvania v. Ritchie, the Court indicated that requests to compel the government to reveal the identity of witnesses or produce exculpatory evidence should be evaluated under due process rather than compulsory process analysis, adding that ''compulsory process provides no greater protections in this area than due process.'' 190
[Footnote 186] United States v. Cooper, 4 U.S. (4 Dall.) 341 (C.C. Pa. 1800) (Justice Chase on circuit).
[Footnote 187] 3 J. Story, Commentaries on the Constitution of the United States 1786 (1833). See Rosen v. United States, 245 U.S. 467 (1918).
[Footnote 188] Washington v. Texas, 388 U.S. 14, 19 -23 (1967). Texas did permit coparticipants to testify for the prosecution.
[Footnote 189] Taylor v. Illinois, 484 U.S. 400 (1988).
[Footnote 190] 480 U.S. 39, 56 (1987) (ordering trial court review of files of child services agency to determine whether they contain evidence material to defense in child abuse prosecution).