New America Foundation fellow Phillip Longman in USA Today on March 13 (synopsized from a longer piece in the March/April issue of Foreign Policy magazine) says basically this: Population equals power; therefore, conservatives/traditionalists have historically and will soon again inherit the earth. Writes Longman:

Childlessness and small families are increasingly the norm today among progressive secularists. As a consequence, an increasing share of all children born into the world are descended from a share of the population whose conservative values have led them to raise large families….
This dynamic helps explain the gradual drift of American culture toward religious fundamentalism and social conservatism.

Do you distrust the army and other institutions? Do you find soft drugs, abortion, homosexuality and euthanasia acceptable? Do you seldom, if ever, attend church? Are you an environmentalist*? These are progressive views, and you are thus part of a literal dying breed.
Juxtapose that to this massive Zogby poll** (30,117 respondents in 48 contiguous states with margin error of +/- 0.6%) conducted March 10-14, and you’ll see why the pro-abortion position is a growing loser for Democrats.
*The logo, right, is from the environmentalist website Voluntary Human Extinction Movement. Its motto, “May we live long and die out,” could not more aptly demonstrate why liberalism is a dying concept.
**The Zogby poll is detailed in today’s LifeNews.com.