Ruben Kihen

Nevada state assemblyman Ruben Kihuen, a 27-year-old Mexican immigrant, is barely known outside his Las Vegas district. But he is being hotly pursued by Hillary Rodham Clinton, Barack Obama and the other contenders for the Democratic presidential nomination.

Mr. Obama summoned him for a tête-à-tête in his hotel suite at Caesars Palace. Christopher Dodd asked him to play a round of golf. Bill Richardson and John Edwards have sought his endorsement, too.