The Hispanic population grew by 4.7 percent last year, while blacks expanded by 1.5 percent and whites by a paltry 0.3 percent. Hispanics cast 6 percent of the vote in 1990 and 12 percent in 2000. If their numbers expand at the current pace, they will be up to 18 percent in 2010 and 24 percent in 2020. With one-third of Hispanics voting Republican, they are the jump ball in American politics. As this vote goes, so goes the future.