On 16 June 2007, WASG merged with Party of Democratic Socialism (PDS) to form The Left (Die Linke).

Oskar Lafontaine, a former major figure on the left wing of the SPD, joined the new party officially on 18 June 2005, and became their North Rhine-Westphalia frontrunner for the general election on 18 September 2005.

The draft programmatic orientation was strongly influenced by the memorandums of the Working group for Alternative Economical Politics which counted one of the party's leading figures, economist Axel Troost, among its members.

The association itself had started as the merger of the groups Initiative Arbeit und soziale Gerechtigkeit (mainly by Bavarian union representatives) and the Wahlalternative ("Electoral Alternative", founded by people in Northern and Western Germany).

Forerunners to such a development were the secession of the Independent Social Democratic Party of Germany (USPD) during World War I, the foundation of the Greens (although these were not founded by disaffected SPD members) in the late 1970s, and the Democratic Socialists (DS) party founded by Karl-Heinz Hansen and Manfred Coppik in the early 1980s.

The federal assembly in Nuremberg of the association WAsG e. V. (20 and 21 November 2004) decided to found a party, something that had never been ruled out as a possible outcome by members of the provisional leadership.

The party's name came into being as Arbeit und soziale Gerechtigkeit – Die Wahlalternative (the abbreviation ASG later had to be changed to WASG, due to a lawsuit).

While some liked to establish it as a purely leftist party of socialist inclination, many others, especially union representatives and former SPD members, aimed to provide a home also for social conservatives and religious people who believe in a strong welfare state.

According to a decision made by the District Court of Düsseldorf, the party was no longer allowed to officially use its abbreviation "ASG".

In that situation, the idea of an electoral coalition with the ideologically similar Party of Democratic Socialism (PDS), led by Gregor Gysi, was put forward by Oskar Lafontaine.

On 10 June 2005, the leaderships of WASG and the PDS agreed to form an electoral alliance for the then-upcoming federal elections in September 2005.