In March 2013, all 27 democratic legislators formed the Alliance for True Democracy (ATD), replacing the Alliance for Universal Suffrage, to show solidarity of the camp to fight for genuine democracy. The ATD put forward a three-channel proposal for the 2017 Chief Executive election during the constitutional reform consultation in 2014. However, the decision of the National People's Congress Standing Committee (NPCSC) on 31 August ruled out the possibility for any candidate not endorsed by Beijing to be nominated for the election, which the pan-democrats accused as a betrayal of the principle of "one person, one vote," The pan-democrats had supported legal scholar Benny Tai's Occupy Central plan of civil disobedience against Beijing's decision, which later turned into a 79-day occupy protest which often dubbed as "Umbrella Revolution". On 18 June 2015, all 27 pan-democrat legislators and Medical legislator Leung Ka-lau voted against the government's constitutional reform bill while the pro-Beijing legislators launched a failed walk-out. The bill was defeated by 28 against 8 for, barely meeting the quorum of 35.