A full 25 percent of voters in this month's election identified themselves as liberals, according to exit polls, a marked increase from 22 percent in 2008. (Conservative is still a more popular identifier, with 35 percent of voters claiming that label.) Still, the "L" word is more popular than it has been since 1976. Conservatives managed to turn "liberal" into an insult in the 1980s, and when Republican icon Ronald Reagan won re-election in 1984, only 17 percent of voters confessed to being liberal. Today that number has ballooned to 25 percent. Why are a growing percentage of Americans calling themselves liberal? Here, three theories:

1. Obama made being liberal cool again

President Obama has "talked about government in a way that many Democrats haven't in recent years," forcefully making the case for a more active role for public agencies in American life, says Aaron Blake at The Washington Post. Obama "may not call himself a liberal," but that's how people see his policies. "Thus, Obama supporters are less reticent to embrace that label." And "the Democratic Party is riding high" — it just snared a majority of the popular vote in two consecutive presidential votes for the first time since the days of Franklin Delano Roosevelt. "They've done it with a president who is regarded as a liberal," and that reinforced "the idea that it's okay to be liberal."

2. Conservatives have been unfairly tarred

It's not that Americans are suddenly gung-ho about liberal politics, says Gary Bauer at Human Events. Voters are still filled with "strong skepticism about whether Obama will be able to accomplish Americans' goals." The Obama campaign simply managed to drive people away from Mitt Romney with a relentless barrage of negative ads smearing him — and, by extension, conservative politics — as "uncaring and disconnected." Republicans can regain this lost ground next time around if they just learn from this loss. "Republican values — strong families, faith, personal responsibility and freedom, among others — are not unique to specific subsets of the electorate. They are universal values, and it is Republicans' job to remind Americans of that fact."

3. America really is changing

"Some of the fastest-growing demographics in the country happen to be the ones that are trending toward the 'liberal' label," says Blake at The Washington Post. That includes "non-religious people (rising from 18 percent liberal in 2004 to 24 percent today), college graduates (from 48 percent to 53 percent) and Hispanics (from 10 percent to 13 percent). Young people, of course, have always been pretty liberal; the label's increasing appeal to these groups means it is gaining steam." Reinforcing this trend is the nation's increasing "tilt to the left when it comes to social policy," as seen in voters' increasing openness to legalizing recreational marijuana use and gay marriage. But the main thing, says Wisconsin state Rep. Leon D. Young at the Milwaukee Courier, is that "the American electorate is indeed changing. It's younger, more multicultural in appearance (Black, Latino and Asian), and definitely less white." Is it any wonder a growing percentage of voters identify as progressives?