Q&A - EU president and foreign policy chief -- What's at stake?

(Reuters) - European Union leaders plan to decide who will be the bloc's president and high representative for foreign affairs at a summit on Thursday.

Following are some questions and answers exploring the powers and responsibilities of the two posts.

WHAT IS AT STAKE?

The president of the Council of EU leaders will be picked for a renewable 2-1/2 year term with the aim of strengthening the current system of a six-month EU presidency that each of the 27 EU states holds in turn. He or she will work closely with a high representative for foreign affairs with enhanced powers intended to raise the EU's global influence.

The president will be the most senior figure in the power structure of a union of nearly 500 million people.

The post is being created under the Lisbon reform treaty, which goes into force on Dec 1. The treaty is intended to facilitate decision-making within the EU and make the bloc a stronger global force.

WHAT WILL THE JOBS INVOLVE?

The definition of the president's role is vague but the main task is to build "cohesion and consensus" in the Council.

The president will represent the EU externally on foreign and security policy, in coordination with the high representative. He or she is the person who would expect to be called by leaders such as U.S. President Barack Obama or Chinese President Hu Jintao when they want to "speak to Europe."

The president will chair the EU Council, which brings EU leaders together for summits at least four times a year. The Council has legislative and budgetary powers which it shares with the European Parliament, and is the main EU policy-making body.

The high representative, appointed for a renewable five-year term, and the president of the European Commission, the EU's executive arm, will also attend Council meetings. The high representative will oversee the External Action Service, an EU diplomatic service being created. The service will have offices around the world to work in conjunction with EU member states' own diplomatic operations.

The idea is that a more united EU will play a more influential role in world affairs, putting it on a par with major powers such as the United States and China.

HOW WILL THE POSTS BE AWARDED?

EU heads of state or government will decide who gets the appointments at a summit over dinner in Brussels. The debate is expected to last into the night, given that ahead of the meeting there was no consensus among the EU's 27 leaders.

Sweden, which holds the EU presidency and is leading negotiations, hopes for a deal accepted by all, but if unanimity proves impossible a decision will have to be reached by qualified majority. That would mean getting the support of 50 percent of member states and 255 of the total 345 votes that are apportioned among the 27 on the basis of population.

Getting a unanimous agreement is complicated by the need to maintain a political, geographical and gender balance.

If the president's job goes to a centre-right candidate, the high representative's post is likely to go a centre-left leader. If the president is from the centre-left, the foreign policy chief would probably be from the centre-right.

A balance also is sought between large and small countries, between countries from northern and southern Europe, and between states in eastern and western Europe.

WHAT KIND OF LEADER WILL GET THE JOB?

Some European leaders believe the president should be a strong and experienced statesman already well known outside Europe who can open doors in world capitals. As some countries have suggested, it should be a leader who can "stop the traffic.

Others favour a low-profile leader skilled at building consensus and brokering deals. Diplomats say the latter view is more popular among the member states.

WHAT HAPPENS NEXT?

Once a decision is made, the president of the European Commission, Jose Manuel Barroso, will draw up a list of 27 commissioners -- one from each member state -- for the European Commission, the EU executive.

They will include the foreign policy chief, who will also hold the post of vice-president of the Commission.

Barroso is expected to present his list in late November or early December. Those nominated will then have to be approved by the European Parliament in hearings in December and January and the new executive is expected to start work in February.

(Editing by Jon Boyle)