Based on data from Pew Research, this generation was consistently D-leaning during the years that the organization tracked their voting patterns (from 1994 to 2004). This generation came of age during the Roosevelt administration and that largely explains their Democratic political leanings. By the Clinton era, the vast majority of them had retired and were collecting Social Security benefits, and the Democratic platform of protecting Social Security against cuts resonated with this cohort.
That makes sense. Social Security was an issue W ran on privatizing.
