With 12 days still to go until Vermont’s Aug. 11 primary election, more voters have requested absentee ballots for the primary than voted both in person and by mail in the 2016 and 2018 primaries. More than 150,000 voters may end up requesting absentee ballots for the primary.
I see three important questions about primary turnout. First, how many of the voters who have requested, or will request, absentee ballots will actually return them? Second, under Vermont’s open primary law, how many voters will choose to vote on each of the three party ballots that they will receive: Democratic, Progressive and Republican? Third, how many voters will choose to cast an in-person ballot at the polls on Aug. 11?
My expectation is that there will be some drop-off between requesting an absentee ballot and actually returning it. The high volume of vote-by-mail applications this year makes it difficult to compare 2020 with previous election cycles, but I would not be surprised if the proportion of requested ballots returned is somewhere between 75% and 80%. If 150,000 ballots are requested, this would mean a vote-by-mail turnout between 112,000 and 120,000.
If another 10,000 to 15,000 people end up voting at the polls on Aug. 11, this would mean total primary turnout of between 122,000 and 135,000. The recent high for turnout in an August primary was 2016, when almost 120,000 ballots were cast. In that year, there were competitive primaries in both the Democratic and Republican parties for governor, since the position was open due to the decision of Gov. Peter Shumlin not to run for a fourth term.
In the last two August primaries, 2016 and 2018, between 60% and 65% of the voters chose to mark the Democratic ballot. Democratic turnout could end up being somewhat higher, in percentage terms, this year, at about 70% of the total. In other states that have already held primaries this year for state and congressional offices, Democratic turnout as a percentage of the total has increased over 2016 and 2018. That pattern could be repeated in Vermont.
Also, the Democratic side of the Vermont ballot includes more competitive contests than the Republican side. Democrats have contested primaries for three statewide offices — governor, lieutenant governor and auditor — as well as competitive primaries for a number of open legislative seats, in particular the Chittenden Senate delegation, where two seats are open because incumbents are running for lieutenant governor.
A relatively small number of voters will cast ballots in person on Aug. 11. The Secretary of State’s Office has issued a directive that will allow towns to set up drive-through or outdoor polling locations for the primary. Under Vermont law, first-time voters must be able to register at a drive-through or outdoor location. For outdoor polling places, a bad weather alternative must be available at the same physical location.
The Secretary of State’s directive also permits towns to establish a secure drop box for the return of completed absentee ballots, so they do not have to be mailed. I would encourage voters mailing marked ballots to put them in the mail by a week prior to the primary, so the ballot will be sure to reach the town clerk’s office before the Aug. 11 deadline. 
Unlike some other states, in which ballots may be counted as long as they are postmarked no later than Election Day, in Vermont absentee ballots must be received before the time the in-person polls close at 7 p.m. on Election Day in order to be counted.
Absentee voters should also make sure that they fill out and sign the form on the “voted ballot” envelope, place the two ballots they are not marking in the “unvoted ballots” envelope, and return both envelopes to their town clerk. Failure to comply with these instructions means your ballot will not be counted. 
Eric L. Davis is professor emeritus of political science at Middlebury College.