Barack Obama's job approval rating in 2014 among white 18- to 29-year-olds is 34%, only three points higher than among whites aged 30 and older

This is the narrowest approval gap between Obama's previously strong support base of white millennials and older white Americans since Obama took office. By contrast, Obama's approval rating was nine percentage points higher among younger whites in 2009, and 10 points higher in 2010. Additionally, while Obama's approval among younger whites matched his overall national rating in his first two years in office, it is now eight points below the national average. These data underscore the gradual erosion of the disproportionately strong support Obama received from young white voters as he took office in 2009 and ran for re-election in 2012. Obama's support among white millennials has factored into his two presidential election successes. Exit polls conducted after the 2012 election, for example, showed that Obama received 44% of the vote of white 18- to 29-year-olds, about six points higher than he received among whites aged 30 and older. Obama's 45% job approval rating among 18- to 29-year-old whites in 2012 mirrored these voting results closely. But Obama's 11-point drop among white 18- to 29-year-olds since 2012 is almost double the six-point drop among the national population and among older whites. From a broader perspective, there is relatively little difference today in Obama's job approval ratings among whites in any of the four major age groups. Whites aged 30 to 49, as well as those 65 and older, have given Obama a 31% approval rating so far in 2014, with 50- to 64-year-olds coming in at 32% and 18- to 29-year-olds at 34%. The spread among age categories was slightly larger in the earliest years of the Obama administration. Although Obama's approval rating has dropped among black, Hispanic and Asian 18- to 29-year-olds from 2009 to 2014, just as it has among white millennials, Obama maintains a much higher level of support among these groups than among whites. Specifically, Obama's approval is 80% among young blacks, 68% among young Asians, and 55% among Hispanic 18- to 29-year-olds - contrasted with his 34% approval among white young adults. Age affects Obama's approval ratings differently among each of these racial and ethnic groups. Obama does slightly less well among black young people than among older blacks, and significantly better among Asians younger than 50 than among those who are older. There is little significant difference in his approval rating by age within the Hispanic population. While Obama is significantly more popular among nonwhites than among whites, he was able to count on proportionately stronger support from young whites than older whites in his 2008 and 2012 presidential election campaigns. Now, his support among white millennials appears to be waning, and these young Americans give Obama an approval rating that is only marginally higher than that among older whites. These findings demonstrate the general importance of race and ethnicity when one talks about Obama's job approval ratings by age. Obama continues to enjoy higher approval ratings among all 18- to 29-year-olds - regardless of race or ethnicity - than he does among the general population, but this is largely attributable to younger age groups in the United States being disproportionately composed of nonwhites. In other words, a big part of the age gap in Obama's approval ratings today is attributable not so much to differences in approval within racial or ethnic groups, but to the fact that the white population in the United States skews older, while the nonwhite population skews younger. The white vote has become an increasing challenge for Democratic presidential candidates in recent years, as well as Senate candidates in many Southern and swing states. A lack of strong support among white voters was instrumental in incumbent Democratic Senator Mary Landrieu's loss in Louisiana's senatorial runoff election. That loss gives the Republicans control of every southern Senate seat from Texas to the Carolinas. While Democrats are likely to be helped in coming years by a growing Hispanic population, Democratic presidential candidates - and senatorial candidates in many states - will continue to need the votes of a substantial minority of white voters in order to put together a winning coalition. Thus, Obama's continuing loss of support among younger white voters highlights one of the potential challenges ahead for Democratic candidates in 2016.