Presidential Primary Debates Can Make — And Break — A Campaign ( fivethirtyeight.com )

It might sound strange, but presidential primary debates are arguably more important than general election debates. Primary voters have weak initial preferences and can vacillate among candidates, so they can be heavily influenced by events like debates. Primary debates do not attract nearly as many eyeballs as general election debates, but they still garner millions of viewers and can persuade more voters than a general election face-off, when most voters have already chosen their partisan camps.

In anticipation of the 2020 presidential election, Democrats have announced plans to hold 12 primary debates, with the first scheduled for June 2019 — nearly eight months before the Iowa caucuses on Feb. 3, 2020,1 the first primary contest. This is three more debates than Democrats scheduled in 2016 and is also a much earlier debate lineup than in the 2016 cycle, when the first Democratic debate was held in October 2015.

It’s hard to pinpoint the exact effect primary debates have on an election, but research by University of Missouri communication professors Mitchell McKinney and Benjamin Warner found that nearly 60 percent of study participants experienced a shift in their candidate choices after watching a debate.

William Benoit, a professor of communication studies at the University of Alabama at Birmingham and author of multiple books on debates, told me that while he doesn’t think that primary debates alone can win someone their party’s nomination, they can cost someone a real shot at winning. A major gaffe or lackluster performance may harm a campaign significantly. Still, Benoit said debates can incrementally help candidates, who can use them as platforms to reinforce messages. We can look at the past two presidential cycles for some evidence