From Wikipedia see the following summary:
Klopfer v. North Carolina, 386 U.S. 213 (1967), was a decision by the United States Supreme Court involving the application of the Speedy Trial Clause of the United States Constitution in state court proceedings. The Sixth Amendment in the Bill of Rights states that in criminal prosecutions “…the accused shall enjoy the right to a speedy trial” In this case, a defendant was tried for trespassing and the initial jury could not reach a verdict. The prosecutor neither dismissed nor reinstated the case but used an unusual procedure to leave it open, potentially indefinitely. Klopfer argued that this denied him his right to a speedy trial. In deciding in his favor, the Supreme Court incorporated the speedy trial protections of the Sixth Amendment against the states.