Could Benenson be right? Has Obama turned an entire generation of voters into lifelong Democrats? The answer, according to political scientists who study partisanship, may well be yes. Voting for a party is a habit, they say, and the habit tends to stick. The Americans who came of age under FDR leaned more Democratic than the electorate as a whole for the rest of their voting lives. Many of today’s oldest voters—who broke for Mitt Romney by a wider margin than any other age group—cast their first, formative ballots in the Eisenhower years. And the Reagan era (spanning his 1980 election, his 1984 reelection, and the 1988 election of his vice president, George H. W. Bush) had a particularly marked effect on the rising voters of the 1980s. The Americans who entered the electorate during that time have remained disproportionately loyal to the GOP compared with voters overall.

In their 2002 book, Partisan Hearts and Minds, the political scientists Donald Green, Bradley Palmquist, and Eric Schickler argue that party loyalty is a tribe-like social identification. Despite parties’ shifting stances on issues, and despite changes in personal beliefs over time, voters tend to continue to affiliate with the same political party. (Think of the “yellow-dog Democrats” of the South, segregationist conservatives who, it was said, would vote for a yellow dog before they’d cast a ballot for a Republican. After national Democrats switched to championing civil rights in the 1960s, these voters did eventually begin to vote with the GOP—but it took decades for them to relabel themselves as Republicans.)

There’s even intriguing new evidence that the act of voting can itself strengthen party loyalty. In a not-yet-published paper, Elias Dinas, a scholar of U.S. politics at the University of Nottingham, compared first-time voters in the 1968 presidential election with people who were otherwise similar but who didn’t vote that year. Dinas found that Nixon voters were subsequently more Republican, and Humphrey voters more Democratic, than peers who hadn’t voted—an indication that casting a ballot makes a person more partisan.

To be sure, not every president bends the electorate toward his party. Pols like Nixon, Clinton, and Bush, who were hardly known for inspiring youth movements, left the electorate much the way they found it. But to Laura Stoker, a UC Berkeley political-science professor who studies partisanship, the fact that young Obama supporters have affirmed their allegiance in two consecutive presidential elections may herald a generation of Democratic-leaning voters that will skew the composition of the electorate far into the future. “The consistency of young people’s support for Obama in 2008 and 2012 suggests a pattern similar to the 1980s,” she told me. “They are going to be more Democratic than they would have otherwise been, because the character of the first votes cast produces or reinforces a Democratic leaning.”