Arizona’s commission-created Congressional maps (Graphic: Arizona Redistricting Commission)

Supreme Court justices will hear arguments Monday morning over an independent redistricting commission created by Arizona voters more than a decade ago in a case that may have the most direct impact on the makeup of the U.S. House of Representatives this term.

Arizona voters passed a ballot initiative back in 2000 creating a bipartisan commission to conduct the decennial redistricting process. The panel, comprised of two Republicans, two Democrats and a fifth member, chosen by the other four, to break ties, was supposed to draw fairer lines, mostly free of partisan gerrymandering.

[This is the best explanation of gerrymandering you will ever see]

But members of the Republican-led state legislature say the U.S. Constitution clearly grants them the right to draw their own districts. Article 1, Section 4 of the Constitution grants legislatures the power to decide “The Times, Places and Manner of holding Elections.”

That clause, the legislature has argued, should supersede the ballot initiative that created the commission. If the court agrees, Arizona’s legislature would likely have to redraw congressional and legislative district lines before the 2016 elections.

And redrawing district lines could have big benefits for Republicans. The party already controls five of nine congressional districts in Arizona, and in 2014 they narrowly missed out on winning two more — seats held by Reps. Ann Kirkpatrick (D) and Kyrsten Sinema (D).

The court will be asked to decide just how much authority the legislature has to draw its own district lines. The legislature, represented before the Supreme Court on Monday by former Solicitor General Paul Clement, contends the Constitution gives them sole power to oversee the process. Currently, the commission’s plans are sent to Arizona’s Secretary of State, who seeks the legislature’s input before finalizing the map.

Supporters of the independent commission will argue the legislature has at least some control over the redistricting process: Legislators get to pick commission members, from a pre-approved list.

A three-judge district court panel rejected the legislature’s suit on a two-to-one vote. That court cited two previous Supreme Court cases, Ohio ex. rel. Davis v. Hildebrandt, decided in 1916, and Smiley v. Holm, a 1932 case out of Minnesota, according to SCOTUSblog.

In the Ohio case, the court ruled that a voter referendum was a part of the legislative process. In the Minnesota case, the court said the Elections Clause in the U.S. Constitution granted each state the ability to choose its own method of holding elections.

The National Conference of State Legislatures filed an amicus brief in support of the legislature’s challenge to the law, while 13 states and the Department of Justice have weighed in on behalf of the commission.

The case has the potential to affect other states that have moved to a bipartisan or nonpartisan redistricting process, too. California, Idaho and Washington each have independent commissions that draw state boundaries. (So do Montana and Alaska, but both of those states have only one representative in Congress.)

Twenty-one states have established redistricting commissions in some form, though most allow the legislature to have a final say.