Generation X, Millennials and the post-Millennial generation make up a clear majority of voting-eligible adults in the United States, but if past midterm election turnout patterns hold true, they are unlikely to cast the majority of votes this November.

As of April 2018 (the most recent data available), 59% of adults who are eligible to vote are Gen Xers, Millennials or “post-Millennials.”

If they vote this year, like they did in the 2014 midterm election, they’re virtually giving their political power away to the Boomers, Silent and Greatest generation, who are ages 54 and older in 2018.

In the 2014 midterm election, which had a historically low turnout, these younger generations accounted for 53% of eligible voters but cast just 36 million votes – 21 million fewer than the Boomer, Silent and Greatest generations, who are ages 54 and older in 2018.

The potential voting power of the Gen Xers, Millennials and post- Millennials continues to grow, partially because of an increase in the number of newly naturalized citizens, but most due to the additional number of post-Millennials (18-21 years old) who become eligible to vote each year.

Meanwhile, the electoral potential of Baby Boomers and older generations has declined since the last midterm. Driven mainly by deaths, there are now 10 million fewer eligible voters among the Boomer and older generations than there were in 2014.

The generational makeup of the electorate matters because, as Pew Research Center surveys have shown, generational differences in political preferences are now as wide as they have been in decades. For example, among registered voters, 59% of Millennials affiliate with the Democratic Party or lean Democratic, while about half of Boomers (48%) and 43% of the Silent Generation identify as or lean Democratic.