The Sixth Amendment

"In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defense."

Anyone being prosecuted for a crime is guaranteed a fair jury, speedy trial, an attorney if they want one, and the chance to confront the witness accusing them of the crime. They have the right to find out what they are being charged with exactly and why they are being held in jail. The accused person also has the right to make anyone attend their trial if they believe that person can help with the case.

The right to a speedy trial makes sure the government doesn't detain citizens for a long period of time before their trial. Without it, possibly innocent people's lives and reputations could be ruined. Delays would also mean that witnesses could forget details and evidence could get lost or destroyed.

https://psmag.com/in-search-of-an-impartial-jury-6d9137a2bc8#.isny4f5jc

Jury selection for the case of the 2013 Boston Marathon bombing is an example of when finding an impartial jury is tough.