The day before what could be a decisive round of talks on Germany's new immigration law, both the Christian Social Union -- sister party to the larger Christian Democrats -- and the Greens are threatening to let the talks collapse. The conservative opposition is demanding further concessions from the ruling coalition of Social Democrats and Greens. The Greens have rejected any further compromises, as pressure mounts on the party leadership from several regional leaders to walk out of negotiations. They say the Greens' positions haven't been properly represented and are worried that there will be changes for the worse if concessions are made on areas such as integration and internal security. The German parliament passed a historic first law on immigration in 2002, but it was later ruled illegal by the upper house of parliament, the Bundesrat. For the past six months, a bipartisan group of 20 parliamentarians has been working to formulate a new law.