The u. s. supreme court uses the fourteenth amendment's due process clause to make most of the individual rights guaranteed by the bill of rights also applicable to the states, by a process called

Due process. Here, The 14th amendment, Section 1 
"All persons born or naturalized in the United States and subject to the jurisdiction thereof, are citizens of the United States and of the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States; nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws."