In the United States v. Wong case of 1976, the Supreme Court ruled that a defendant's right to confront witnesses against him is not violated when an interpreter is used in court proceedings. The defendant, Wong, was charged with conspiracy to distribute heroin and claimed his Sixth Amendment rights were violated because he could not directly cross-examine a witness who spoke only Chinese. The Court held that as long as the interpretation is competent and reliable, it does not infringe upon the accused’s constitutional rights. It noted that interpreters are often necessary for ensuring fair trials where language barriers exist between defendants or witnesses and courts.

In the dissenting opinion for United States v. Wong, Justice William Rehnquist argued that the majority's decision to allow a defendant in a criminal trial to challenge their conviction based on an interpreter's errors was flawed. He contended that there were no constitutional grounds for this ruling and it could potentially open up countless convictions to challenges over minor translation discrepancies. Furthermore, he pointed out that many other countries with multiple languages do not provide such rights and manage effectively nonetheless. He also expressed concern about how courts would determine what constitutes a significant error by an interpreter, suggesting it could lead to endless debates over semantics rather than focusing on substantive issues of guilt or innocence.