Federal habeas review did not extend to those in state custody until almost a century after the nation's founding. During the Civil War and Reconstruction, as later during the War on Terrorism, the right to petition for a writ of habeas corpus was substantially curtailed for persons accused of engaging in certain conduct. In reaction to the former, and to ensure state courts enforced federal law, a Reconstruction Act for the first time extended the right of federal court habeas review to those in the custody of state courts (prisons and jails), expanding the writ essentially to all imprisoned on American soil. The federal habeas statute that resulted, with substantial amendments, is now at 28 U.S.C. § 2241. For many decades, the great majority of habeas petitions reviewed in federal court have been filed by those confined in state prisons by sentence of a state court for state crimes (e.g., murder, rape, robbery, etc.), since in the American system, most crimes have historically been a matter of state law.