Sentence:  Alain, who is proud of choosing the extreme right but still didn't want his real name printed, is one of the 6.4 million Le Pen voters who are now the <WSD>kingmakers</WSD> in deciding who becomes the next president of France. If the Socialist François Hollande topped the poll, beating the rightwing president, Nicolas Sarkozy, and gaining momentum for returning the left to the presidency for the first time in a generation, it is Le Pen whose high showing and third place now holds the election in the balance. 
Meaning of the word marked with <WSD> tags:  Someone who has strong influence over the choice of a leader.