Excerpt: States have an extensive and complicated shared power relationship with the federal government in regulating various aspects of the health insurance market and in enacting health reforms. As part of state-based responses to federal health reform legislation, members of at least 11 state legislatures are using the legislative process to seek to limit, alter or oppose selected federal actions, including single-payer provisions and mandates that would require purchase of insurance. Based on actions initially in Arizona, several states propose or may propose state constitutional amendments, using language such as[.]