Bavarian conservatives hold Treaty hostage

Germany's Christian Social Union, the Bavarian sister party of Chancellor Angela Merkel's conservatives, is demanding legislative changes that could delay Berlin's ratification of the European Union's Lisbon Treaty.

Their stance puts them at odds with Ms Merkel and could have consequences for the future of the Treaty, which is designed to streamline decision-making in the broader 27-nation bloc.

Germany is one of four member states, alongside the Czech Republic, Ireland and Poland, that have not ratified the Treaty. All EU states must approve it for it to enter into force.

Below are some questions and answers about the CSU's stance, how the ratification process could play out in Germany and the potential impact at EU level.

Why hasn't Germany approved the Treaty?

Both houses of Parliament approved the Treaty last year, but President Horst Koehler declined to sign off on it until Germany's Constitutional Court had ruled on a series of complaints by euro-sceptic lawmakers.

The court decided last month that the Treaty was compatible with German law, but said changes needed to be made to domestic legislation to ensure the German Parliament had a role in vetting decisions taken in Brussels on sensitive areas such as the military, taxes and religion.

Ms Merkel wants new legislation incorporating changes mandated by the court to be ready for approval by the Bundestag lower house of Parliament by September 8. It could then pass through the upper house Bundesrat in mid-September, allowing Mr Koehler to sign off before a federal election on September 27.

What is the CSU demanding and why?

The CSU has seized on the ruling and is demanding that decisions taken in Brussels be subjected to even greater scrutiny than the court is requesting.

It wants Parliament to be able to take part in a broad range of government decisions on EU matters, a step which the party says would mean changes to three articles in Germany's Constitution. The CSU also wants the Constitutional Court to have the last word on interpreting the Lisbon Treaty.

The changes demanded by the CSU would likely delay the approval process beyond the election. Ms Merkel and her Social Democrat coalition partners fear that if the CSU got its way, future German leaders would be incapable of taking policy decisions at regular EU summits without consulting Parliament.

By taking this stance, the CSU leadership is hoping to appease elements within the party who oppose the Lisbon Treaty.

The position also helps the party differentiate itself from Ms Merkel's Christian Democrats, boosting its profile in Bavaria, where euro-scepticism runs deep, ahead of the September election.

When is Germany likely to approve the treaty?

The most likely scenario is that a compromise is found with the CSU over the summer, allowing ratification to go through before the election.

There is a risk, however, that the CSU sticks to its hard line in a bid to win votes. That could push parliamentary approval back to November or even later.

What would be the impact of a German delay?

If Germany has not ratified the treaty by the election, it could be seized upon by treaty opponents in Ireland, which is due to hold a second referendum on Lisbon on October 2 after initially rejecting it last year.

Euro-sceptic Presidents in the Czech Republic and Poland, who have indicated they will sign the treaty if Ireland approves it, could also refuse to go ahead as long as Germany has not completed the ratification process.