Cases on the right to arms in state constitutions can provide useful guidance for courts addressing Second Amendment issues. Although some people have claimed that state courts always use a highly deferential version of "reasonableness," this article shows that many courts have employed rigorous standards, including the tools of strict scrutiny, such as overbreadth, narrow tailoring, and less restrictive means. Courts have also used categoricalism (deciding whether something is inside or outside the right) and narrow construction (to prevent criminal laws from conflicting with the right to arms). Even when formally applying "reasonableness," many courts have used reasonableness as a serious, non-deferential standard of review. District of Columbia v. Heller teaches that supine standards of review, such as deferring to the mere invocation of "police power," are inappropriate in Second Amendment interpretation. This article surveys important state cases from the Early Republic to the present, and explains how they may be applied to the Second Amendment.