Independent fact-checkers say their work informs voters and holds politicians accountable. “Campaigns are very aware that fact-checkers are watching them,” said Bill Adair, editor of PolitiFact. PolitiFact’s web traffic has shot up this year and “it’s just gone off the charts on debate nights,” Adair said.

But proponents also acknowledge that fact-checking isn’t going to stop political spin. “We’re never going to change the behavior of candidates,” said Brooks Jackson, director of FactCheck.org. “It’s wired into the political system. We award power to the people who persuade us.”

Increasing polarization in the electorate also works against fact-checking efforts. It’s easier for politicians to get away with twisting the truth “in a polarized world where Republicans don’t believe hardly anything a Democrat says and Democrats don’t believe hardly anything a Republican says,” Hetherington said.

The burden is on voters to seek out the truth, fact-checkers say. But partisan voters often ignore criticism of their preferred candidate, and not all independents are motivated enough to follow the twists and turns of an increasingly wonky policy debate. If the voters tune out, or decide “that it’s just both sides lying,” then fact-checking hasn’t served its purpose, Jamieson said.