Young Americans between the ages of 18-29 have become more Democratic since 2007 according to the latest Gallup Poll.

But the reason is not their support for gay marriage or any other social issue. It's mostly a demographic change. There are more non-whites in that age group than ever before and that is skewing the numbers toward the Democrats.

From 1993 to 2003, 47% of 18- to 29-year-olds, on average, identified as Democrats or said they were independents but leaned to the Democratic Party, while 42% were Republicans or Republican leaners. That time span included two years in which young adults tilted Republican, 1994 and 1995, when Republicans won control of Congress. Since 2006, the average gap in favor of the Democratic Party among young adults has been 18 percentage points, 54% to 36%.

This Democratic movement among the young has come at a time when senior citizens have become more Republican. The broader U.S. population has shown more variability in its party preferences in recent years, shifting Democratic from 2005 to 2008, moving back toward the Republican Party from 2009 to 2011, and showing modest Democratic preferences in the last two years.

Younger Americans Now More Racially Diverse

A major reason young adults are increasingly likely to prefer the Democratic Party is that today's young adults are more racially and ethnically diverse than young adults of the past. U.S. political preferences are sharply divided by race, with nonwhite Americans of all ages overwhelmingly identifying as Democrats or leaning Democratic.

Gallup estimates that 54% of 18- to 29-year-olds are non-Hispanic white and 45% nonwhite, compared with 71% non-Hispanic white and 29% nonwhite in 1995, the first full year Gallup measured Hispanic ethnicity.

In 2013, 62% of nonwhite Americans between the ages of 18 and 29 were Democrats or Democratic leaners, while 25% were Republicans or Republican leaners. That 37-point Democratic advantage, though sizable, is slightly lower than the average 42-point advantage from 1995 through 2013.

But young adults are not more Democratic solely because they are more racially diverse. In recent years, young white adults, who previously aligned more with the Republican Party, have shifted Democratic. From 1995 to 2005, young whites consistently identified as or leaned Republican rather than Democratic, by an average of eight points. Since 2006, whites aged 18 to 29 have shown at least a slight Democratic preference in all but one year, with an average advantage of three points.

The takeaway here is the young white vote which not only has been trending Democratic but is falling as a percentage of the total youth vote. Considering that Democratic narrative over the last 5 years - amplified by the press - that Republicans are a bunch of tired, racist, old white men, it shouldn't be surprising that there has been a shift in party ID. It just isn't "hip" to be Republican and until that perception can be changed, GOP hopes will continue to rest on the proposition that young voters will stay home on election day.