The exterior of the U.S. Supreme Court on March 26, 2012.National Journal

The U.S. Supreme Court avoided a congressional shake-up Monday morning, upholding the constitutionality of independent redistricting commissions rather than striking down the congressional maps in Arizona and possibly several other states.

The court ruled 5-4 in favor of Arizona's redistricting commission, rejecting an argument by the state's Republican legislators that the Constitution only gives the authority to draw legislative and congressional lines to state legislatures.

The Constitution's Election Clause says that state legislatures have authority to regulate elections. But the Court's opinion, written by Justice Ruth Bader Ginsburg, ruled that that applies as much to voters—who created the state's commission via a successful ballot measure—as it does to the state's elected lawmakers. The state's constitution, the Court cited, specifies that any legislative power belonging to the legislature also belongs to the people.

(RELATED: How the Supreme Court Could Change Congressional Maps in Arizona (and Other States))

"Invoking the Elections Clause, the Arizona Legislature instituted this lawsuit to disempower the State's voters from serving as the legislative power for redistricting purposes," Ginsburg wrote. "But the Clause surely was not adopted to diminish a State's authority to determine its own lawmaking processes."

Justice Anthony Kennedy joined the Court's four liberal justices to support the ruling.

In his dissent, Justice Antonin Scalia called it counterintuitive that the word "legislature" in the Constitution can apply to anything but a literal legislature.

(RELATED: The Pernicious Effects of Gerrymandering)

"[T]he majority's resolution of the merits question ("legislature" means "the people") is so outrageously wrong, so utterly devoid of textual or historic support, so flatly in contradiction of prior Supreme Court cases, so obviously the willful product of hostility to districting by state legislatures, that I cannot avoid adding my vote to the devastating dissent of the Chief Justice," Scalia wrote.

If it had ruled in favor of the legislature, the Court likely would have voided the congressional lines in six states: Arizona, Alaska, California, Idaho, Montana, and Washington.

The partisan political repercussions in this ruling are mixed: Both Democrats in Arizona and Republicans in California stood to lose congressional seats if redistricting powers had been given back to their respective state legislatures.

Leading up to the ruling, Kathay Feng, national redistricting director for Common Cause, which supports the commissions, said she has talked to activists in Ohio, North Carolina, Michigan, "and many other states" about passing ballot measures that create similar commissions, now that they have been ruled constitutional.

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