A struck jury is a multi-step process of selecting a jury from a pool. First potential jurors are eliminated for hardship. Second jurors are eliminated for cause by conducting voir dire until there is a pool available that is exactly the size of the final jury (including required alternates) plus the number of peremptory challenges available to each side. Then the two sides exercise their peremptory challenges on the remaining pool, usually alternating. This procedure "has its roots in ancient common law heritage".