HARRISBURG, Pa. (AP) – A primary election like none other in state history awaits Pennsylvania voters Tuesday, when those who have not contributed to the flood of mail-in ballots may encounter new machines designed to improve security by creating a paper record. Polling places in some counties have been moved or consolidated to cope with a pandemic-driven drop in election volunteers, and special social distancing rules will be in place.

Download The New And Improved CBS Philly App!

The result of the highest profile contests on the ballot are a foregone conclusion, as President Donald Trump and former Vice President Joe Biden are the presumptive major-party nominees.

The only statewide races are for the “row offices” – attorney general, auditor general and treasurer.

Democratic Attorney General Josh Shapiro is unopposed in seeking his party’s nomination, as is Pittsburgh lawyer Heather Heidelbaugh for the GOP nod. There is a six-candidate Democratic primary and a lone Republican seeking the nominations for attorney general, as incumbent Eugene DePasquale is term-limited. Unopposed in the treasurer primary are incumbent Democrat Joe Torsella and Republican Stacy Garrity.

All 18 of the state’s members of the U.S. House of Representatives are seeking reelection, although only two have primary opposition from within their own party – suburban Philadelphia Rep. Brian Fitzpatrick, a Republican, and Pittsburgh Rep. Mike Doyle, a Democrat.

In the Legislature, all 203 House seats and half the 50-member Senate are up this year. The most notable vacancies were created by the retirements of House Speaker Mike Turzai, R-Allegheny, and Senate President Pro Tempore Joe Scarnati, R-Jefferson.

There are 17 retirements in the state House, which currently has a 110-93 Republican majority, and two in the Senate, where the GOP, with one independent, holds a 29-21 margin.

Primary voters will also pick delegates and alternates for the two major parties’ presidential nominating conventions.

The election was postponed from April because of the COVID-19 pandemic, and in the meantime Pennsylvania voters have requested more than 1.8 mail-in ballots and returned about 1 million.

Before a new state law passed last year, those who did not wish to cast their ballots in person had to provide one of a limited number of permitted excuses to qualify for absentee ballots.

The unexpected volume of no-excuses mail-in ballot requests has proven to be a challenge for county elections officials, and they are warning that election night results are likely to be delayed. Where those delays will occur and how long it will take to get results are open questions.

At the same time, about a third of counties will be using new voting systems for the first time. The conversion to new machines caused some problems in November, including malfunctions in Northampton County that one official likened to a three-alarm fire.

Copyright 2020 The Associated Press.