<P> The right to confront and cross-examine witnesses also applies to physical evidence; the prosecution must present physical evidence to the jury, providing the defense ample opportunity to cross-examine its validity and meaning . Prosecution generally may not refer to evidence without first presenting it . </P> <P> In the late 20th and early 21st century this clause became an issue in the use of the silent witness rule . </P> <P> The Compulsory Process Clause gives any criminal defendant the right to call witnesses in his favor . If any such witness refuses to testify, that witness may be compelled to do so by the court at the request of the defendant . However, in some cases the court may refuse to permit a defense witness to testify . For example, if a defense lawyer fails to notify the prosecution of the identity of a witness to gain a tactical advantage, that witness may be precluded from testifying . </P> <P> A criminal defendant has the right to be represented by counsel . </P>

The sixth amendment gives a u.s. citizen the right to