It is decision day for Europe but common ground is in short supply as a crunch summit gets underway. Key differences remain as leaders gather to thrash out a deal on a new European Union constitution. And, arriving in Brussels, Britain's Prime Minister Tony Blair admitted that tough talking lies ahead. London is fighting to prevent the EU from having the final say in issues ranging from foreign policy to taxation. But that is only one potential source of conflict facing summit host Silvio Berlusconi. The Italian Prime Minister, whose country currently holds the EU's rotating presidency, said that it would take a miracle for a deal to be reached. He added, however, that "sometimes miracles happen." European Commission President Romano Prodi believes it is better to delay a deal than reach an unsatisfactory agreement. Voting rights is proving the thorniest of issues as the EU prepares to expand. It is a subject that has mobilized "new kid on the bloc" Poland, whose Prime Minister Leszek Miller has been adamant that he will lead his country's delegation despite the fact that he is recovering from a helicopter crash. With change on the horizon, Poland and Spain are clinging to a complex voting system agreed three years ago, which gave them almost as many votes as Germany, although it has twice their population. **PHOTO CAPTION*** Workers set up flags in preparation for a two-day EU summit, starting Friday, at the European Commission headquarters in Brussels, Thursday, Dec. 11, 2003. (AP Photo/Domenico Stinellis)