Dickerson v. United States, 530 U.S. 428 (2000), upheld the requirement that the Miranda warning be read to criminal suspects and struck down a federal statute that purported to overrule Miranda v. Arizona (1966).

What is the importance of dickerson v. united states? Let's have some stream of consciousness first.
The relevant sentence in the passage is: Dickerson v. United States, 530 U.S. 428 (2000), upheld the requirement that the Miranda warning be read to criminal suspects and struck down a federal statute that purported to overrule Miranda v. Arizona (1966). So, the answer is upheld the requirement that the Miranda warning be read to criminal suspects.