LISBON Portugal's general election campaign ended on May 16 for a vote that Prime Minister Luis Montenegro is expected to win, but with no guarantee he can form a more stable government. Montenegro's center-right Democratic Alliance (AD) is tipped to win 34 percent of the vote, ahead of the Socialist Party (PS) on 26 percent, according to a poll by the Portuguese Catholic University published by local media on May 16. The recently formed far-right Chega ("Enough") party could take 19 percent of