After falling from power, the DS became divided into rival wings led by Boris Tadić and Dragan Đilas. Tadić left the DS in early 2014 to form a breakaway group initially called the New Democratic Party (Nova demokratska stranka, NDS), which contested the 2014 Serbian parliamentary election in a fusion with the Greens of Serbia (Zeleni Srbije, ZS) and in alliance with other parties. Konstantinović sided with Tadić and joined the NDS, appearing in the twenty-eighth position on its list."Konstantinović istupio iz DS", Blic (Source: Tanjug), 6 February 2014, accessed 30 September 2017.Избори за народне посланике Народне скупштине одржани 16. и 23. марта 2014. године – ИЗБОРНЕ ЛИСТЕ (11 БОРИС ТАДИЋ - Нова демократска странка - Зелени, ЛСВ - Ненад Чанак, Заједно за Србију, VMDK, Заједно за Војводину, Демократска левица Рома), Republic Election Commission, Republic of Serbia, accessed 10 July 2021. The list won eighteen mandates, and he was not re-elected to the assembly. He also received the largely honorary 105th position (out of 110) on the NDS's list in the 2014 Belgrade city assembly election.Službeni List (Grada Beograda), Volume 58 Number 15 (5 March 2014), p. 22. Election from this position was a mathematical impossibility, and the list did not cross the electoral threshold in any event. Later in the year, the NDS renamed itself as the Social Democratic Party (Socijaldemokratska stranka, SDS).
