White voters of all ages were less likely to back Democrats in 2014 than in past elections, helping Republicans nationwide but most acutely in the South - and overpowering Democratic efforts to turn out their core supporters among blacks and Hispanics

For the Democrats, dominating the vote among minorities isn't enough to win elections today - and it won't be in the future if the GOP is able to run up similar margins among whites, who still make up a majority of voters in every state. "The rule of thumb was Democrats could win with 90% of the African-American vote and 40% of the white vote,' said Merle Black, a political science professor at Emory University in Atlanta. But now very few Democrats could think about getting 40% of the white vote. They're trying to get 30%. In the Deep South states, from South Carolina to Louisiana, it's very hard for the Democratic candidate to get 25% of the white vote." Republicans running for seats in the House won 60% of the white vote, while Democrats won the backing of 89% of African-Americans and 62% of Hispanics. Those margins are nearly identical to the 2010 midterm elections. But Democrats won more of the white and Hispanic vote in 2006, the last midterm elections in which the party won control of the House. White voters last tilted in Democrats' favor in a midterm in 1990, and were a swing group in the 1980's. Outside the South, whites broke for Republicans by an average of eight percentage points on Election Day 2014. But in ten Southern states with an election for Senate on the ballot, Republicans won the white vote by an average of 42 points. Democrats garnered so little support among whites in Georgia, Louisiana, Mississippi, South Carolina and Texas that a majority of those voting for the Democratic candidate were non-white. In North Carolina, though incumbent Democratic Sen. Kay Hagan was widely credited with running a solid campaign, she carried just 33% of the white vote - down from 39% in 2008 - and lost. White voters under age 30 backed Hagan by close to a 2-1 margin six years ago as they helped sweep President Barack Obama into office. This time, in a midterm election, the younger white voters who cast ballots in North Carolina broke just as decisively for Hagan's Republican opponent, state House Speaker Thom Tillis. The only states in which Democratic Senate candidates improved their overall support among whites were Minnesota, Oregon and Mississippi, a Southern state where Travis Childers managed to grow the Democratic share of the white vote from 8% in 2008 to 16%. Republican voters tend to be older, wealthier, more educated and more likely to be white than Democratic voters. Democrats have not won a majority of white women since 1992.