Monday's big election law news came from the Supreme Court's penultimate decision of the term upholding Arizona's congressional districts.

But before handing down its last three decisions, the court made voting-rights advocates happy by deciding not to review a different election case.

"Arizona citizens can continue to participate in voter registration drives without worrying about not having proof of citizenship documents," Shirley Sandelands, of the League of Women Voters of Arizona, said in a statement Monday.

The case, Kobach, et al. v. Election Assistance Commission, et al., was about whether Arizona and Kansas could require voters to prove their citizenship when registering to vote with the so-called "federal form." Kansas Secretary of State Kris Kobach led the suit against the U.S. Election Assistance Commission, which was an appeal of a lower court decision.

The Supreme Court did not take up a voter ID case brought by Arizona and Kansas. (CQ Roll Call File Photo)

Both Kansas and Arizona have state laws that require applicants to prove their citizenship when applying to vote with state forms (for state or federal elections). But the U.S. EAC denied the states' requests to have their citizenship laws applied when would-be voters use the standardized federal form.

The Supreme Court had already ruled in 2013 that state proof-of-citizenship laws couldn't be applied when people try to register with the federal form. The states' direct request to the EAC was a last-ditch effort to get around that.

By not hearing the case, the Supreme Court effectively upheld the decision of the 10th Circuit Court of Appeals, which ruled against Arizona and Kansas in November 2014, saying the EAC did not have to modify its form to meet state laws. Under the federal form, would-be voters need only swear under penalty of perjury that they are citizens.