It was established in December 2014 by the Israeli Labor Party and Hatnuah to create a joint electoral list to contest the 2015 elections with the hope of unseating Prime Minister Benjamin Netanyahu.

However, tension between the Union's competing factions resulted in its dissolution in early January 2019, ahead of that year's April election.

[5] Livni and Labor leader Isaac Herzog initially said that if the alliance were to win enough seats to lead the next government, they would rotate in the post of Prime Minister, with Herzog serving for the first half of the Knesset's four-year term and Livni for the second half,[6] though Livni announced on 16 March 2015 that only Herzog would serve as prime minister.

[8] The Green Movement also had representation on the list through the addition of Yael Cohen Paran, selected by Livni, on a spot (No.

[21][22] Its success was mostly in affluent areas, and it won the highest number of votes in 28 of Israel's 33 wealthiest communities.