Since the US Supreme Court ruled, in 2010, that corporations and labor unions can spend freely on political advertisements, unprecedented amounts of money have poured into American elections.
Who has benefited from the influx of cash? Overwhelmingly, the Republican Party, according to new research by Columbia political scientist Carlo Prato. He and Nour Abdul-Razzak, of the University of Chicago, and Stephane Wolton, of the London School of Economics and Political Science, recently conducted one of the first studies to quantify the effects of the Citizens United ruling on election outcomes. After comparing the results of state legislative elections held between 1990 and 2015, the researchers found that in the twenty-three states that formerly restricted corporate and union political spending, Republicans have won a three-to-four-point greater share of the vote since 2010 than would otherwise have been expected, given national voting trends. Not surprisingly, this appears to have won the GOP many tight races: the party’s share of legislative seats in these states has jumped by an average of 5 percent.
In states with many powerful corporations and relatively low union membership, such as Texas, Mississippi, Idaho, and North and South Carolina, the Citizens United ruling appears to have increased Republican seat share by as much as twelve points. In states with high union membership, such as California, New York, Illinois, and Pennsylvania, the case has had no discernible effect on the partisan balance of legislatures.
“In many states, Democrats are getting crushed,” Prato says. “In those with strong unions, they are merely holding their own.”
