Two companion measures would have separately paused the commission and implemented new district boundaries.
Had the initiatives qualified for the November ballot and been approved by voters, the revised congressional map would have taken effect for the 2028 elections.
Supporters argued the changes were necessary to redraw district lines, while opponents contended they would have significantly altered the state’s current redistricting process.
In three separate opinions, the Colorado Supreme Court ruled that each proposed measure violated the state’s constitutional “single subject” requirement, preventing them from moving forward, NBC News reported.
“Changing the constitutionally mandated frequency of redistricting — however temporary the change — is not merely a mechanism to administer the new congressional district map,” Chief Justice Monica Marquez wrote in one unanimous decision.
“Instead, it represents a seismic shift to Colorado’s longstanding redistricting process enshrined in the state constitution,” her opinion noted further.
In a second unanimous opinion, the Colorado Supreme Court concluded that dividing the original proposal into two separate ballot measures still failed to satisfy the state’s single-subject requirement.
A spokesperson for Coloradans for a Level Playing Field did not immediately comment on the rulings.
The legal challenge comes amid a broader national debate over mid-decade congressional redistricting.
The issue gained momentum last year after President Donald Trump encouraged Republican-led states to consider redrawing congressional maps in an effort to strengthen the GOP’s narrow majority in the U.S. House of Representatives.
Democrats have faced additional hurdles in pursuing similar efforts in states where independent redistricting commissions control the map-drawing process, including Colorado.
Virginia Democrats advanced a comparable ballot measure this year that sought to bypass the state’s independent redistricting commission and adopt a new congressional map.
Although voters narrowly approved the proposal, the Virginia Supreme Court later blocked it from taking effect, NBC News noted.
