The promise ("Work with school districts and teachers to implement a statewide ban on cellphones in Colorado classrooms") is a documented 2026 Colorado gubernatorial-campaign proposal by Bennet, explicitly contrasted with rival Phil Weiser's "let districts decide" position (Axios Denver, Alamosa Citizen, and Bennet's own campaign site all confirm the proposal and its statewide-mandate framing). Implementing a statewide classroom cellphone ban is a state executive/legislative function requiring the governorship; Bennet is a sitting U.S. Senator with no authority over Colorado classroom policy, so his only path to fulfilling the promise ran through winning the governor's office. He lost the June 30, 2026 Democratic gubernatorial primary to Attorney General Phil Weiser (54.7%-45.3%, AP-called), so he never obtained the office the promise depended on and never got a genuine chance to act on it. He actively championed the proposal as a candidate (ruling out IGNORED/ABSTAINED/MISALIGNED/HOSTILE) but took no implementing action because none was possible before the primary loss foreclosed it (ruling out ATTEMPTED/PARTIAL/FULL/CHAMPIONED as an enacted outcome). NO_OPPORTUNITY is correct. Confidence held slightly below certainty because one could alternatively frame this as UNRATABLE given his ongoing Senate tenure, but the promise is inherently office-contingent on a governorship he did not win.