In his announcement, Miller said that the new party would be a "true leftist" alternative to the LiD coalition.

In 2007 elections Leszek Miller started from the Self-Defence of the Republic of Poland.

The Polish Left party was formed when the Prime Minister and many other members of parliament withdrew from the Democratic Left Alliance, which Miller had headed for many years.

Before the 2019 elections, Polish Left got into litigations with Democratic Left Alliance and put up three candidates for senators including Monika Jaruzelska who was criticized by some left-wing politicians for conservatives views.

Leszek Miller, current MEP from SLD declared that it is likely to create a new leftist party or coalition in opposition to the SLD and The Left.