Colorado voters to decide on constitutional amendment that would require approval from an independent commission and the state supreme court for mid-decade redistricting maps

Voters in Colorado will decide on a ballot measure related to mid-decade redistricting on Nov. 3, 2026.

The initiated constitutional amendment — known as Initiative 256 — would require any mid-decade redistricting plan to be approved by both the state's independent redistricting commission and the Colorado Supreme Court.

The Colorado secretary of state's office certified Initiative 256 for the ballot on Aug. 31, 2026, announcing that its proponents submitted 141,866 valid signatures, surpassing the required minimum of 124,238.

As of 2026, Article V, Section 44 of the Colorado Constitution requires the independent commission and the state supreme court to approve redistricting maps following the U.S. decennial census.

Initiative 256 is supported by Advance Colorado, an organization that describes its mission as "[pushing] back on the progressive policies that have put our state on the wrong track." Kristi Burton Brown, executive vice president of Advance Colorado, said that the measure "puts exactly what Colorado voters want in the state constitution — a prohibition on any mid-cycle maps from being drawn to benefit a specific political party. Instead, voters want independent maps that prioritize their communities."

On June 29, 2026, the state supreme court ruled that other initiatives that would have redrawn maps before the decennial census were unconstitutional. In its 7-0 decision, Chief Justice Monica Márquez said that undoing the state's independent commission would be a "seismic shift to Colorado's longstanding redistricting process enshrined in the state constitution," and that "changing long-settled law by modifying the timing, frequency, criteria, and entity responsible for congressional redistricting represents a significant change beyond the proponents' stated central purposes."

Opponents of Initiative 256 filed a separate petition with the state supreme court, stating that it violated both the single-subject rule and included impermissible language. However, the state supreme court did not take the case, thereby allowing it to appear on the ballot.

Opponents of Initiative 256 challenged the measure before the Title Board and the Colorado Supreme Court. They argued that it violated the single-subject rule, that its ballot title did not accurately describe its effects, and that the phrase purposefully favoring one political party was undefined and constituted impermissible language. The Colorado Supreme Court affirmed the Title Board’s decision to set a title for the initiative on May 29, 2026, allowing proponents to circulate petitions

In 2018, voters in Colorado decided on a ballot measure—Amendment Y—that created the current 12-member independent commission for congressional redistricting. Voters approved Amendment Y, which received 71.37% of the vote. Before Amendment Y passed, the Colorado General Assembly voted on new maps, which the governor could veto.

Voters in California and Virginia have also recently decided on ballot measures related to mid-decade redistricting:

In 2025, voters in California approved Proposition 50, which allowed the state to use a new, legislature-drawn congressional district map for 2026 through 2030.
In 2026, voters in Virginia approved a constitutional amendment that would have allowed the General Assembly to redraw congressional districts between Jan. 1, 2025, and Oct. 31, 2030, if another state redrew its districts for reasons other than completing decennial redistricting or complying with a court order. However, the Virginia Supreme Court overturned the amendment, so it did not take effect.

Initiative 256 is the thirteenth measure that Colorado voters will decide on in Nov. 2026, appearing alongside eleven other citizen initiatives and one legislative referral. One additional citizen initiative is currently in the certification process, with signatures submitted to the Secretary of State's office. Initiative 256 requires a 55% majority to pass.

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