Nothing less than the future of Europe's power sector is at stake in the long-running takeover battle of Endesa, the Spanish utility, by Germany's E.ON. The $71 billion deal, announced in February, has dragged on amid legal challenges. At issue: the cross-border ownership of one country's power giant by another. The battle heated up in October when Spanish conglomerate Acciona bought up 20% of Endesa in a backdoor attempt to thwart E.ON's deal. Observers say E.ON, which upped its offer earlier this year, will prevail.