Germany's highest court rejected on Thursday a legal challenge to the country's ratification of the European Union constitution, clearing the way for parliament to vote on the charter in May, Reuters repoted here today. Peter Gauweiler, a member of parliament for the opposition Christian Social Union, had asked the Federal Constitutional Court to stop parliament from ratifying the constitution. Gauweiler, who wants a referendum on the issue, said the court ruling left him free to repeat his challenge after parliament votes on ratification next month. Germany's lower house, or Bundestag, is due to vote on the charter on May 12. The upper house, or Bundesrat, is scheduled to vote on May 27, in a move timed to give a boost to the "Yes" campaign in a French referendum two days later. Some of the 16 federal states that sit in the upper house had indicated they may delay approving the charter past May 27, in order to increase their say in future EU legislation. --More 0006 Local Time 2106 GMT