The coalition broke in 2005 as a result of opposition to the policies of Res Publica's minister of justice Vaher.

At the time of its merging with Pro Patria, it was led by Taavi Veskimägi, a former Minister of Finance.

Until the 2007 parliamentary elections, Res Publica was the largest party in the Riigikogu, with 28 of 101 seats.

A decision was made to form a new party, named Pro Patria and Res Publica Union (Isamaa ja Res Publica Liit), after approval by general assemblies of both merging political forces.

The union took third place in the 2007 elections, which, though they resulted in a loss in the combined parties' strength in Parliament, was a stronger than expected showing.