A long-term tracking of party identification by age group shows a significant shift away from the GOP among the “late Boomer/Gen-X” age group and a tilt towards the Democratic party by the youngest voters.

According to the Pew Research Center study released today, voters aged 18-29 are considerably more likely (58 percent to 33 percent) to align themselves with the Democratic Party than the Republican Party. Just four years ago, the margin for Democrats among this group was 51 to 40 percent. Among Generation Y voters (born in 1977 or after), the gap also widened: in 2004, they preferred Democrats 52 to 39 percent; in 2008, 57 to 33 percent.

This obvious trend toward the Democratic Party is evident across other age groups, as well, and has been particularly noticeable with the “late Boomer/Gen-X” age group (1956-76). Statistics for voters born in that 20-year period show a 15 percentage point shift since 2004 ‘ four years ago, the Republican Party had a 3 percentage point edge in that age group; today’s results show a 12 percentage point gap in favor of the Democratic Party.

The survey responses from 2004 were based on polls conducted October 2003 through November 2004, and responses for 2008 were based on polls conducted October 2007 through March 2008.