BOSTON (AP) — Massachusetts voters face a lot of choices, and not just for president: They're filling an open U.S. House seat, weighing two hotly contested statewide ballot questions and deciding whether to reelect some longtime incumbents to Congress.

A record number of voters already cast ballots early or by mail, changing the complexion of Tuesday's election.

Democratic U.S. Sen. Edward Markey is vying for another six-year term Tuesday, hoping to fend off a challenge from Republican Kevin O’Connor.

Markey, who rebuffed a high-profile primary challenge from Democratic U.S. Rep. Joe Kennedy III in September, is taking on O’Connor in a state that leans heavily Democratic.

In the state’s 4th Congressional District, Democratic Newton City Councilor Jake Auchincloss is hoping to become the newest member of the state’s all-Democratic congressional delegation by defeating Republican Julie Hall. The open seat is currently held by Kennedy, who opted not to seek reelection after deciding to challenge Markey.

Voters also weighed the fate of two questions on the ballot.

The first would expand the state’s “Right to Repair” law by giving car owners and independent auto shops greater access to data related to vehicle maintenance and repair.

Car repair shops and auto parts suppliers said the measure would guarantee car owners access to the repair information needed to bring their cars to auto shops as vehicles become more computerized. Automakers cast the question as a data grab by third parties who want to gather personal vehicle information.

The second question would make major changes to the way ballots are cast and tallied in future elections in Massachusetts by introducing ranked choice voting.

Under that system, voters would be given the option of ranking candidates in order of their preference — one for their top choice, two for their second choice, and so on.

If no candidate receives a majority of the first-choice votes, the candidate with the fewest votes would be eliminated. Voters who ranked the eliminated candidate as their first choice would have their votes counted instead for their second choice. The process repeats until one candidate receives a majority of the vote and wins.

Republican Gov. Charlie Baker is among the opponents of ranked choice voting, calling it complicated and costly. Polls suggested a close race between the “yes” and “no” camps.

Four of the state’s remaining eight Democratic House incumbents are facing Republican challengers.

Rep. Jim McGovern, who represents the state’s 2nd Congressional District, is hoping to fend off GOP challenger Tracy Lovvorn, while 5th Congressional District Rep. Katherine Clark is trying to defeat a challenge from Republican Caroline Colarusso. Former presidential candidate Rep. Seth Moulton, who represents the 6th Congressional District, is hoping to defeat GOP challenger John Paul Moran, while Rep. William Keating, who represents the 9th Congressional District, is hoping to beat back a challenge from Republican Helen Brady and independent Michael Manley.

Two Democratic incumbents — 1st Congressional District Rep. Richard Neal and 3rd Congressional District Rep. Lori Trahan — ran unopposed. Two others — 7th Congressional District Rep. Ayanna Pressley and 8th Congressional District Rep. Stephen Lynch — faced little-known independent challengers.

___

Find AP’s full election coverage at APNews.com/Election2020.