Quiet political shifts in U.S. as more blacks are elected

State Representative Melanie Levesque, center, campaigning for re-election in Brookline, New Hampshire. Blacks make up less than 1 percent of the population in her district. (Cheryl Senter for The New York Times )

Political analysts say such electoral gains are quietly changing the political landscape, increasing the number of black lawmakers adept at crossing color lines as well as the ranks of white voters who are familiar, and increasingly comfortable, with black political leadership.