Cases with consequences: recent Supreme Court rulings were game-changers for the states - and not just because of the decisions on health care and same-sex marriage.

• Author: Soronen, Lisa
• Position: Supreme Court

The U.S. Supreme Court's recent rulings on same-sex marriage and Obamacare drew enormous interest from court watchers and the public alike. Several other cases--on redistricting, fair housing and Medicaid, for example--got less notice, but could have far-reaching consequences for the states.

Here's a recap of what was decided and a note on what lies ahead as the court enters its 10th year with Chief Justice John Roberts in the center seat.

Redistricting

By a 5-4 decision in Arizona State Legislature v. Arizona Independent Redistricting Commission, the court held that the Constitution's Elections Clause permits voters to vest congressional redistricting authority entirely in an independent commission. The ruling is an affirmation of direct democracy. NCSL filed an amicus brief supporting the Arizona Legislature.

Justice Ruth Bader Ginsburg's majority opinion relies on the history and purpose of the Elections Clause, and the "animating principle of our Constitution that the people themselves are the originating source of all the powers of government," in ruling that redistricting commissions may operate independently of state legislatures.

Founding-era dictionaries typically defined legislatures as the "power that makes laws." In Arizona, that includes the voters, who may pass laws through initiatives.

EPA Regulations

In Michigan v. EPA, the justices held 5-4 that the Environmental Protection Agency acted unreasonably in failing to consider cost when deciding whether to regulate mercury emissions from power plants. Twenty-three states challenged the regulations.

The Clean Air Act requires the EPA to regulate air pollution from stationary sources based on how much pollution the source emits. But the agency may only regulate emissions from fossil-fuel-fired power plants if it finds that regulation is "appropriate and necessary."

EPA found it appropriate and necessary to regulate mercury emissions, but did not consider costs when determining whether power plants should be regulated. The majority of the court, in an opinion written by Justice Antonin Scalia, concluded that the agency's interpretation of appropriate and necessary to exclude costs wasn't reasonable.

The opinion leaves unanswered questions, including how the EPA may account for costs and whether the agency may consider ancillary benefits in the cost-benefit analysis.

Fair Housing

In Texas Department of Housing and Community Affairs v. Inclusive Communities Project, the court held 5-4 that disparate-impact claims may be brought under the Fair Housing Act.

In a disparate-impact case, a plaintiff claims that a policy used by a government agency, private real estate firm or developer isn't intentionally discriminatory but nonetheless has a disproportionately adverse impact on...