UNITED STATES  .-By art. iii. s . 2 of the constitution, the trial of all crimes, except in cases of impeachment, is to be by jury . By art. v. of the amendments no person can be held to answer for a capital or otherwise infamous crime unless on a presentment or indictment of a grand jury . Considerable changes have been made by state legislation in the direction of enlarging the powers of courts of summary jurisdiction .