Voters have rejected Amendment 80, a ballot measure that would have enshrined the right to school choice in the Colorado Constitution, according to unofficial results from the Secretary of State’s Office.

The ballot measure has received 1,246,984 votes in favor, or 48%, and 1,345,276 votes in opposition, or 52%, as of noon Thursday.

The Associated Press officially called the race Thursday morning, after results remained too close to call for over 36 hours after polls closed. Because it would have added language to the Constitution, the amendment needed at least 55% approval to pass, but it fell almost 7 percentage points short.

“We’re thrilled that despite deceptive campaign tactics, Amendment 80 was soundly defeated,” Colorado Education Association President Kevin Vick said in a Wednesday news release. “Public schools in Colorado serve 95% of students, and they must be protected from those who would attempt to dismantle them for profit. Colorado voters have made it clear that they are not interested in thinly veiled attempts to bring voucher programs to our state.”

The ballot measure was authored by conservative advocacy organization Advance Colorado, which quickly received opposition from the Colorado Education Association, American Civil Liberties Union of Colorado, Colorado Rural Schools Alliance, Colorado PTA and the Colorado Democrats.

Proponents of Amendment 80 argued the amendment would protect school choice from future legislation, while opposers argued that the amendment’s vague language could be interpreted to take funding away from public schools and open the door to future voucher programs, which have proven costly in states like Arizona.

Public Schools Strong, a registered political action committee opposing Amendment 80, managed to raise roughly $4.9 million leading up to the election and spent over $4.6 million. Of the contributions, over $4 million came from the National Education Association.

The majority of outreach in support of Amendment 80 came in the form of mailers and text messages paid by 501(c)4 nonprofit Colorado Dawn, which does not disclose its donors. The nonprofit — which appointed Advance Colorado President Michael Fields as its treasurer — received criticism for its misleading campaign ads shared with residents via text messages throughout October and November, which falsely suggested that Colorado leaders including Gov. Jared Polis, U.S. Sen. John Hickenlooper and Vick supported the measure.

The decision by Colorado voters not to pass Amendment 80 does not impact school choice as it currently exists in Colorado. The state’s most recent system of school choice was passed by the legislature in 1994 and allows students to attend any public school for free regardless of their district of residence. The legislation also allows students to choose a nonpublic education option, such as private or home schools.