The researchers argue that local
political protests provide important
signals to voters as well as to candidates
and potential challengers. For voters,
they can focus attention. To incumbent
lawmakers, they are signals about
intensity of local content or discontent.
For prospective challengers, they can
signal the incumbent’s vulnerability.
Indeed, the paper finds that an increase
in liberal protest activity correlates with
an increase in the number of “quality”
Democratic challengers, such as those who
have held elected offices before. The odds of
a solid challenger entering a congressional
race climbed from 20% to 50% as the
intensity of protest activity increased.
“It’s a form of information-gathering,”
Gillion says. “When politicians run for
office, they try to know every single issue
in their backyard as well as the sentiments
of their constituents. Protests are a way
of signaling discontent, and they inform
politicians about the most salient issues.”
Gillion adds that the volume and
intensity of progressive protests have been
higher in 2018 than at any time since the
Other studies, including a new one by
Robb Willer of Stanford, find that violent
protests can lead people to think poorly
of the protesters. However, Soule and
Gillion say they found little evidence that
protests produce a backlash in actual voting
Was it enough to affect the 2018 midterm
“Based on these findings, unequivocally,
yes,” says Soule. Δ
Sarah A. Soule is the Morgridge
Professor of Organizational Behavior
at Stanford GSB.
“Many people are skeptical that
protests matter to electoral outcomes, but
our paper finds that they have a profound
effect on voter behavior,” says Soule.
“Liberal protests lead Democrats to vote
on the issues that resonate for them, and
conservative protests lead Republicans to
do the same. It happens on both sides of
the ideological spectrum.”
On average, a wave of liberal protesting
in a congressional district can increase
a Democratic candidate’s vote share by 2%
and reduce a GOP candidate’s share by 6%.
A wave of conservative protests, like those
by the Tea Party in 2010, will on average
reduce the Democratic vote share by 2% and
increase the Republican share by 6%.
a profound effect
on voter behavior.
It happens on
both sides of
On top of that, big protests by
progressives have spurred increases in
the quality of Democrats who decide to
challenge incumbents. (Conservative
protests haven’t had the same impact
motivating Republican challengers,
however.) That seems to be what has
happened in 2018, when record numbers
of women both marched in the streets and
decided to run as Democrats for Congress,
but the pattern isn’t unique to this year.
The study is based on a detailed analysis
of both local protest activity and voting
patterns in every congressional election
from 1960 to 1990.
The data on protests came from news
reports. Soule and Gillion focused only on
local protests, which they scored by both
their ideological leaning and their intensity
To rate the protests on an ideological
spectrum, the researchers looked at each
protest’s focal issues. Not surprisingly,
given the anti-war and civil rights
movements of the 1960s and 1970s, 90%
of the protests during those decades were
on the left side of the political spectrum.
But the share of conservative protests
increased gradually to 14% in the ’80s and
21% by 1990.
To rate “salience,” Soule and Gillion
looked at whether the protests attracted
large numbers of people; had organizational
backing; attracted police presence; or
resulted in damage, injuries, or death.
For example, in the 1968 election
of Abner Mikva, a liberal challenger in
Illinois, the district saw 40 protests that
year, which were scored at a salience
level of 54 — fairly high, but nowhere
near as high as the protests during some
other races. Mikva defeated both the
Democratic incumbent in the primary
and his Republican opponent in the
Interestingly, conservative protests
of similar intensity appear to give
Republicans a proportionately bigger boost
in vote share. Soule and Gillion say that
probably reflects the fact that conservative
street protests were rare until the
1990s, which probably made them more
electrifying to Republican voters.