Political candidates used to try to woo the great middle—voters who might be persuaded to vote either way if a message was to their liking. But that segment is just about gone, replaced by a more polarized electorate, according to a new study.

From the 1950s through the 1980s, the number of “floating voters,” or swing voters, amounted to between 10% and 15% of the voting public. That figure has now fallen to about 5%, according to “Polarization and the Decline of the American Floating Voter” by Michigan State political scientist Corwin Smidt. He found that voters currently have stronger identification with political parties and are more consistently loyal to them.

“By making it easy for Americans to recognize party differences, polarization has reduced ambivalence and indecisiveness and provided a strong and consistent ideological anchor to Americans’ presidential preferences across time, even for independents and the less aware,” Smidt wrote.

The new reality has paid off for Republicans, who have made institutional changes in states they control, such as gerrymandering and voter suppression. They accomplish that lock in their power structure via the legislative branch, while Democrats’ path to power is through winning the White House. The advantage for Republicans is that they can lose a few House or state legislature seats here and there and still maintain control, but if Democrats don’t win a presidential election, they’re out of luck, according to New York magazine’s Jonathan Chait.

The trend, Smidt says, means that things like shifts in the economy or other events make less difference in an election; most voters support the candidate of their party no matter what else is going on. That means that parties have less incentive to appeal to the diminishing number of swing voters and instead concentrate their messages on what they know their base wants to hear—and what will motivate them to vote.

-Steve Straehley

To Learn More:

Politics in a Country Where Nobody Changes Their Mind (by Jonathan Chait, New York Magazine)

The Astonishing Decline of the American Swing Voter (by John Sides, Washington Post)

Polarization and Decline of the American Floating Voter (by Corwin D. Smidt, Michigan State University)

Independents Outnumber Both Democrats and Republicans in 44 of 50 States (by Noel Brinkerhoff, AllGov)

California Has More Official Independent Voters that Aren't Actually Independent (by Ken Broder, AllGov California)

Americans Identifying as Independents Hits Record High as Republican ID Drops to 30-Year Low (by Noel Brinkerhoff, AllGov)