President Obama said at a fundraiser Wednesday night that Democrats suffer in midterm elections in large part because black and Latino voters -- among other groups -- don't turn out to vote.

"Our voters are younger, more unmarried women, more African-American and Latino voters," Obama said at an event in Houston. "They get excited about general elections; they don't get as excited about midterm elections."

Obama added: "...we have this congenital disease, which is in midterm elections we don't vote at the same rates."

Obama's remarks appear to be a pretty clear reference to a poll released earlier in the week that showed these groups -- described by Democratic pollster Stan Greenberg as the Rising American Electorate -- are much less keen on voting in 2014 than are other, more Republican demographics.

Increased turnout among these voters was a big reason Obama won in both 2008 and 2012 -- forming what Democrats saw as their new coalition -- but Democrats are concerned that they can't count on these voters to vote when Obama isn't on the ballot.

The president has repeatedly cautioned Democrats against complacency in the midterms, in which Republicans are now widely projected to take over the Senate.