Why Republican voter restrictions are a race against time

With their drive to erect new obstacles to voting, particularly across the Sun Belt, Republicans are stacking sandbags against a rising tide of demographic change.

In many of the states where Republicans are advancing the most severe restrictions -- including Georgia, Arizona and Texas -- shifts in the electorate's composition are eroding decades of virtually uncontested GOP dominance. In each of those states -- and others such as North Carolina, South Carolina and, in a slightly different way, Florida -- the GOP still holds a statewide advantage primarily because of its strong performance among older, non-college-educated and non-urban White voters. But in almost all those states, the Republican edge is ebbing amid two powerful demographic currents: an improving Democratic performance among white-collar voters in and around the states' rapidly growing major cities, and the aging into the electorate of younger generations defined by kaleidoscopic racial diversity.