New research by Peter Buisseret, assistant professor in the University of Chicago Harris School of Public Policy, and a coauthor shows that in times of intense polarization, outsiders are more likely to win elections than establishment candidates if they are able to prevail within established parties.

“Our framework shows that when polarization between parties is strongest, party establishments are most vulnerable to entry from outsiders, and elites have the least control over their nominating process,” said Buisseret.

Established parties become an increasingly attractive target for outsider candidates despite their unorthodox views when there is substantial polarization between the parties, Buisseret and his coauthor, Richard Van Weelden of the University of Pittsburgh, find. Though an outsider’s policies are misaligned with party elites, they may have substantial appeal for rank-and-file voters.

Buisseret’s research shows that:

In the interests of party unity, party leaders with the ability to block an outsider candidate will often choose not to do so.

Outsider candidates, if they are able to attain the party nomination, will be stronger in a general election against an establishment candidate.

In a highly polarized environment, outsider politicians with a party nomination will attract some non-establishment voters from the other party, while retaining their own party’s base.

“Despite initial opposition, outsiders anticipate that so long as they win the nomination, they will be able to unite the party in its common desire to defeat the opposing party’s candidate,” Buisseret said. “This makes a primary victory an especially valuable prize, even for candidates that are not totally aligned with the party’s views.”

Outsider candidates like Donald Trump, Bernie Sanders and Roy Moore have had significant success in established parties despite their misalignment with party orthodoxy, and have particularly done so in times of increased partisanship. The incentive to join a party that does not necessarily reflect one’s views lessens in times of decreased partisanship, as voters are more likely to be swayed between choices.

“In light of the increase in polarization documented in recent decades, our prediction that primary entry is relatively more attractive to outsiders in periods of heightened partisanship is consistent with the fact that Ross Perot pursued a third-party candidacy in the 1990s, when the environment was less polarized, while Donald Trump instead pursued a primary challenge for a major party in a hyperpolarized 2016,” said Buisseret.

The full research report is available here.