How Much Have Closed Primaries Hurt Bernie Sanders?

In the course of their coverage of the Democratic primary race, the media has casually brought up that Bernie Sanders does better in open or semi-closed primary races (where independent and no party affiliation voters are allowed to participate) than in closed primaries that include only Democrats. What I haven’t seen anyone do is examine the exact impact that the exclusion of independent voters has had on this primary process so far. For starters, let’s compare the results of contests where independents could vote with the results of contests where independents were excluded. For the sake of this exercise, we won’t count closed primaries or caucuses where voters could switch to Democrat at the polling place.

11 Closed Primaries/Caucuses so far (Independents Excluded)

Hillary Clinton has won of these (Louisiana, Florida, Arizona, New York, Connecticut, Delaware, Maryland, and Pennsylvania).

Bernie Sanders has won 3 of these (Colorado, Maine, and Wyoming).

30 Open, Semi-Open, or Same-Day Registration Primaries/Caucuses so far (Independents Included or Able to Easily Switch to Democrat)

Hillary Clinton has won 15 of these (Iowa, Nevada, South Carolina, Alabama, Arkansas, Georgia, Massachusetts, Tennessee, Texas, Virginia, Mississippi, Illinois, Missouri, North Carolina, and Ohio).

Bernie Sanders has won 15 of these as well (New Hampshire, Minnesota, Vermont, Oklahoma, Kansas, Nebraska, Michigan, Utah, Idaho, Washington, Alaska, Hawaii, Wisconsin, Rhode Island, and Indiana).

In open or semi-open contests, Sanders appears to win the support of independent voters by varying amounts depending on the region of the country. According to CNN exit polls, 53% of independents who voted in the South Carolina Democratic primary favored Sanders. Sanders also scored 55% of independent voters in Arkansas, 66% in Massachusetts, 69% in Oklahoma, 54% in Tennessee, 52% in Texas, 58% in Virginia, 71% in Michigan, 69% in Illinois, 67% in Missouri, 58% in North Carolina, 66% in Ohio, and lost them by slim margins in Alabama and Georgia, two states where he was otherwise crushed.

Although there appear to be some slight geographic differences, the share of independent voters in independent-friendly primaries appears to often fall between 20% and 30%. Across independent-friendly primaries in the Midwest, for example, about a quarter of the voters in each open primary identified as politically independent (27% in Michigan, 27% in Wisconsin, 22% in Indiana, and 24% in Ohio). In New England, the share of independent voters was even higher: 33% in Massachusetts and 40% in New Hampshire.

Independent-friendly Democratic primaries in the southeast seemed to have smaller shares of independent voters. The primaries in Georgia and Alabama were 20% independents, and South Carolina’s was only 16%. However, in other Southern states the numbers were higher: 22% in Virginia, 23% in Tennessee, 26% in Texas, and 28% in North Carolina.

Now let’s take a look at the results of the five closed primaries for which we have exit poll data.


Hillary Clinton celebrates her Florida primary victory in West Palm Beach. Getty Images

FLORIDA (March 15): Exit poll data shows that 18% of voters in Florida’s closed Democratic primary identified as independent. They couldn’t actually be registered independent, of course, but many of these voters presumably registered as Democrats just to be able to vote in primary elections. If we assume (not unreasonably) that an independent-friendly primary in Florida might have been 25% independent voters, about 158,482 voters are brought into the process, 55% of whom vote for Sanders.

Actual Florida results, closed primary: Clinton 1,097,400 votes (64.4%), Sanders 566,603 votes (33.3%), 38,875 votes for other candidates. Clinton 141 delegates, Sanders 73.

Florida results, hypothetical open primary: Clinton 1,162,378 votes (62.4%), Sanders 653,768 votes (35.1%), 45,214 votes for other candidates. Clinton 139 delegates, Sanders 75.


Hillary Clinton and Bernie Sanders at a Democratic primary debate in Brooklyn, New York. Reuters

NEW YORK (April 19): New York, with some of the strictest election laws in the country, had an October deadline for independent voters to register as Democrats. As a result, New York’s share of independent-indentifying voters in the Democratic primary was the lowest of any state with available exit polling: 14%. The exit polling data also shows that a whopping 72% of those independents who did switch parties in time favored Sanders. If we again assume a 25% share of independents in a hypothetical open primary in New York, the results get significantly closer.

Actual New York results, closed primary: Clinton 1,054,083 votes (58.0%), Sanders 763,469 votes (42.0%). Clinton 139 delegates, Sanders 108.

New York results, hypothetical open primary: Clinton 1,129,835 votes (54.1%), Sanders 958,260 votes (45.9%). Clinton 134 delegates, Sanders 113.

If independents made up 30% of the Democratic primary electorate (a rosy situation for Sanders, but not impossible given the huge turnout amongst independents in nearby Massachusetts, Vermont, and New Hampshire), Clinton’s share of the vote drops to 52.4% and Sanders’ rises to 47.7%. In this optimistic-for-Sanders hypothetical, Clinton’s margin of victory is about 105,000 votes.

PENNSYLVANIA (April 26): Pennsylvania’s 15% share of independent voters was nearly as small as New York’s. In another hypothetical open primary where 25% of voters are independents, Pennsylvania gets very close, because again, 72% of voters in the state who identified as independents favored Sanders.

Actual Pennsylvania results, closed primary: Clinton 918,689 votes (55.6%), Sanders 719,955 votes (43.6%), 14,303 votes for other candidates. Clinton 106 delegates, Sanders 83.

Pennsylvania results, hypothetical open primary: Clinton 977,724 votes (52.0%), Sanders 883,436 votes (47.0%), 18,844 votes for other candidates (1.0%). Clinton 101 delegates, Sanders 88.

CONNECTICUT (April 26): Although Connecticut independents were better at making their voices heard than their counterparts in the other April 26 closed primaries, they still only made up 20% of the Democratic primary electorate. It’s probably safe to presume that that share would reach 30% in an open primary, since it was 33% in neighboring Massachusetts and 40% or greater in New Hampshire and Vermont, the other two New England states for which there is exit polling.

Actual Connecticut results, closed primary: Clinton 170,075 votes (51.8%), Sanders 152,410 votes (46.4%), 5,837 votes for other candidates (1.8%). Clinton 28 delegates, Sanders 27.

Connecticut results, hypothetical closed primary: Sanders 188,919 votes (50.0%), Clinton 181,422 votes (48.0%), 7,317 votes for other candidates (2.0%). Sanders 28 delegates, Clinton 27.

MARYLAND (April 26): CNN’s exit polling says that only 51% of independent voters in Maryland favored Sanders. While this seems unlikely, I’ll avoid making up a hypothetical number. If only 51% of independent voters favor Sanders, adding more independents to the electorate is unlikely to significantly shift the outcome.

Now, let’s make some guesstimates about the six closed primary/caucus states for which we don’t have exit poll data.

COLORADO (March 1): Although this state was already favorable for Sanders, let’s assume a shift of about 3%, similar to the shifts in other northern states.

Actual Colorado results, closed caucuses: Sanders 59.0%, Clinton 40.3%, 0.7% for other candidates. Sanders 41 delegates, Clinton 25 (these have shifted slightly in favor of Sanders after strong showings at state-level caucuses. The original results should’ve been 39-27 for Sanders).

Colorado results, hypothetical open caucuses: Sanders 62.0%, Clinton 37.3%, 0.7% for other candidates. Sanders 43 delegates, Clinton 23 (assuming a similar shift for Sanders based on the state-level caucuses).

LOUISIANA (March 5): Let’s guesstimate that the hypothetical shift in Louisiana’s vote will be similar (about a 2% gain for Sanders) to the shift in Florida, the only other southern state to hold a closed primary.

Actual Louisiana results, closed primary: Clinton 71.1%, Sanders 23.2%, 5.7% for other candidates. Clinton 37 delegates, Sanders 14.

Louisiana results, hypothetical open primary: Clinton 69.1%, Sanders 25.0.% for Sanders, 5.9% for other candidates. Clinton 35 delegates, Sanders 16.

MAINE (March 6): In a Sanders-heavy New England state, let’s shift the vote about 3.5%, similar to what happened in our hypothetical Connecticut open primary.

Actual Maine results, closed caucuses: Sanders 64.3%, Clinton 35.5%, 0.2% for other candidates. Sanders 16 delegates, Clinton 9.

Maine results, hypothetical open caucuses: Sanders 67.3%, Clinton 32.5%, 0.2% for other candidates. Sanders 17 delegates, Clinton 8.

ARIZONA (March 22): Considering that 71% of independent voters in neighboring Nevada chose Sanders, let’s shift the Arizona results about 3%.

Actual Arizona results, closed primary: Clinton 57.6%, Sanders 39.9%, 2.4% for other candidates. Clinton 42 delegates, Sanders 33.

Arizona results, hypothetical open primary: Clinton 54.6%, Sanders 41.7%, 2.6% for other candidates. Clinton 40 delegates, Sanders 35.


Bernie Sanders speaks to supporters in Laramie, Wyoming. Blaine McCartney, Wyoming Tribune Eagle

WYOMING (April 9): Wyoming’s closed caucuses are one of the few reasonable explanations for Sanders’ unexpectedly small victory here despite neighboring independent-friendly states like Utah and Idaho choosing Sanders with nearly 80% of the vote. Let’s boost Sanders to 60% in Wyoming with the addition of independent voters.

Actual Wyoming results, closed caucuses: Sanders 55.7%, Clinton 44.3%. Sanders delegates, Clinton 7.

Wyoming results, hypothetical open caucuses: Sanders 60.0%, Clinton 40.0%. Sanders 8 delegates, Clinton 6.

DELAWARE (April 26): Let’s assume that Delaware is similar enough to Maryland that opening the primary wouldn’t make much of a difference.

According to FiveThirtyEight, Clinton leads Sanders by 285 delegates (1,705 to 1,420) as of May 8. Factoring in every shift in delegates based on my calculations and guesstimations, Sanders would have 21 more delegates right now if every primary and caucus thus far had allowed independents to vote. Sanders would have 1,441 delegates to Clinton’s 1,684, shrinking her delegate lead to a still-substantial 243.

Although I believe that closing off independent voters from the most important part of the political process is wrong regardless of what effect it has, it does not appear that Bernie Sanders would be much closer to becoming the Democratic nominee if closed primaries and caucuses were done away with.

Currently, in order to finish with a majority of pledged delegates, Sanders has to win 65.4% of the remaining delegates, or 606 of the 926 left. In our hypothetical closed primary-free scenario, at this point in the race Sanders would have to win 63.2% of the remaining pledged delegates, or 585.

The exclusion of independent voters from primaries and caucuses does appear to be a significant problem for Bernie Sanders, but perhaps not his most significant problem. His name recognition, especially at the start of the process, was minute compared to that of Hillary Clinton. If Bernie Sanders’ campaign had received half the media coverage of Donald Trump’s, this race might be a different story.



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