Massachusetts voters prepare to decide on several key races in the September 1 primary election.

From the Republican gubernatorial race and a clash for the U.S. Senate to key races for seats on Beacon Hill and the battles for District Attorney in Suffolk County and beyond, here’s what voters need to know.

Republican gubernatorial — Minogue vs. Shortsleeve

On the Republican ballot, Massachusetts voters will have the chance to decide who takes on Gov. Maura Healey in the general election in November: Mike Minogue or Brian Shortsleeve.

Minogue, a billionaire and first-time political candidate, brings a wealth of experience from the private sector who for nearly two decades led the medical technology company Abiomed, acquired by Johnson & Johnson in 2022.

Shortsleeve served as the chief administrator and later the acting general manager of the MBTA under former Gov. Charlie Baker. He calls himself a “turnaround specialist” in campaign materials from his experience improving this agency.

Both candidates served in the U.S. military. Shortsleeve served in the Marine Corps and Minogue as an Army Airborne Ranger and West Point graduate.

Mike Minogue and Brian Shortsleeve will face off on September 1 for the chance to take on Gov. Maura Healey in November. Mark Stockwell/Boston Herald

Minogue has hung his hat on the landslide victory he captured at the Massachusetts Republican Convention, taking home 70% of the vote from delegates. Shortsleeve made the ballot by a hair, just squeezing by the 15% delegate vote threshold.

Minogue has ignored requests from the Shortsleeve campaign to participate in primary debates and has focused on taking on Healey in the general election.

On the other hand,  Shortsleeve has centered his campaign around attacking both Healey and Minogue, which has earned him some criticism from fellow Republicans.

The two candidates share many ideas about the commonwealth’s future, but the abortion issue may be what separates them most. Shortsleeve is pro-choice, while Minogue says he is pro-life.

The abortion issue has regained importance in deep-blue Massachusetts after Healey this month signed into law a controversial bill that removes all restrictions on abortions after 24 weeks gestation.

U.S. Senate — Markey vs. Moulton

The Democratic primary race between Sen. Ed Markey and Congressman Seth Moulton is less separated by political visions, but something else: age.

Moulton has centered his campaign around promoting himself as the “fresh face” Capitol Hill needs to replace the aging establishment — a group epitomized by Markey, who has served in Congress for 50 years. He was first elected to the U.S. House in 1976 — two years before Moulton was born.

Markey has countered this by highlighting the need for someone with his experience in Washington, while also pushing his record of fighting for liberal Democratic values during his lengthy tenure.

Composite of Herald photos

U.S. Rep. Seth Moulton is taking on U.S. Sen. Ed Markey. (Herald file photos)

With few real political differences between the two, Markey and Moulton have resorted to mudslinging. They have exchanged accusations of insider trading and accepting campaign donations from corporate PACs. They’ve also railed against President Trump, with Markey and Moulton mentioning the president frequently during their three summertime debates.

Markey has remained the frontrunner in the race, according to polls, starting with a sizable 19-point lead over Moulton in polls taken back in November. Moulton had considerably closed that gap over the spring and summer months, but a recent UMass Amherst/WCVB poll gave Markey a massive 30-point advantage in August.

The primary winner will face Republican candidate John Deaton in the general election.

8th Congressional District — Lynch vs. Roath

Longtime Congressman Stephen Lynch is facing a primary challenge from Democratic candidate Patrick Roath.

Lynch was first elected in 2001, replacing the outgoing former Congressman Joe Moakley. He has held various House committee assignments during his tenure, currently serving as a ranking member of the House Oversight Committee.

Lynch’s campaign paints him as a proven, experienced, “common sense” candidate that will stand up to Republicans and President Trump. Like Sen. Markey, the 71-year old Lynch is fending off attacks from Roath on his age and his 25 year stay on Capitol Hill.

Longtime Congressman Stephen Lynch is fending off a challenge from the younger, more progressive Patrick Roath. Nancy Lane/Boston Herald//Courtesy of Roath campaign

The younger Roath, 39, is promoting himself as a “voting rights advocate and attorney” who will serve as a younger, fresher face to “take on Trump’s authoritarian agenda and deliver bold solutions for working families.” Roath also boasts his resume, which includes serving as an aide to former Gov. Deval Patrick and former President Obama.

“I’m running against a member of Congress who’s been an elected official since I was five years old, Roath told CNN News Central last month. “Isn’t it time for the next generation to get someone new in there to do something a little different and that’s more tailored to what the times require?”

Lynch has countered these attacks with highlighting Roath’s Connecticut upbringing, as well as his political support from private equity groups and the pharmaceutical industry.

1st Congressional District — Neal vs. Whalen

Voters in western Massachusetts will face a similar situation in the 1st Congressional District: an aging Democratic incumbent trying to hold onto his seat from a younger, more progressive challenger.

Longtime Congressman Richard Neal is running to defend his seat against 39-year old high school teacher Jeromie Whalen.

Neal, who paints himself as a “lunch-bucket” Democrat, was first elected to Congress in 1989 after serving as Springfield Mayor for five years prior. Currently, the 77-year old Neal serves as a ranking member of the House Ways and Means Committee — which he chaired until 2023.

Longtime Congressman Richard Neal is running to defend his seat against newcomer Jeromie Whalen. Staff Photo Chris Christo/Boston Herald//Courtesy Jeromie Whalen for Congress

Whalen holds both a bachelor’s degree and Ph.D. from UMass Amherst, degrees he earned in 2011 and 2018, respectively. He has worked as a high school teacher and for the nonprofit local community media outlet.

In addition to going after Neal’s age and over 35 years in Congress, Whalen has zeroed in on Neal’s acceptance of campaign donations from corporate PACs. Whalen promotes himself as an “everyman” candidate who will provide a fresh start and more progressive perspective on Capitol Hill, particularly highlighting his support of Medicare For All against Neal’s opposition to it.

Neal is fending off attacks on his age and lengthy tenure by promoting the need for his vast wealth of political experience and representation of western Massachusetts. Otherwise, Neal has adopted the classic incumbent playbook by not mentioning Whalen’s name or responding to any attacks launched by him.

Neal and Whalen will participate in a televised debate next week on WWLP-TV.

State Senate: First Suffolk — Collins vs. Gayle

Boston Mayor Michelle Wu’s failed push to increase commercial tax rates has taken center stage in a state Senate race between incumbent Nick Collins and his challenger Latoya Gayle.

Collins, a South Boston Democrat, led the effort to kill Wu’s tax shift bill in the Senate two years ago. Wu in turn went on the offensive this year and campaigned fiercely against him by endorsing his primary opponent and lobbyist, Gayle.

The race has escalated a years-long public feud between Wu and Collins, with the two trading jabs over what Wu has characterized as Collins’ move to block Boston homeowners from seeing a tax break through her stalled legislation.

State Sen. Nick Collins is fending off a primary challenge by Boston Mayor Michelle Wu-backed candidate Latoya Gayle. Nancy Lane/Boston Herald//Michelle Wu Facebook photo

Wu’s bill, which Gayle supports, would have shifted more of the city’s property tax burden from homeowners to commercial property owners for several years.

Collins last month undercut Wu on the matter by tucking a property tax relief clause into the state’s economic development bill to blunt what he called “Boston’s unnecessary tax increase on homeowners.”

His alternative tax relief clause was passed unanimously by the state Senate, leading Wu to slam Collins for being “an obstacle, not a partner” on tax relief.

Gayle, a political newcomer, is vying to unseat Collins. He was first elected to public office in 2010, to the House of Representatives, and has held his First Suffolk Senate seat in 2018.

State Senate: Suffolk & Middlesex — Brownsberger vs. Lander

It’s the battle of Boston mayors in the race between political newcomer Daniel Lander and the state Senate’s President pro tempore William Brownsberger, as Wu’s influence beyond the city will be tested in the race.

Wu is backing Lander, a former senior aide in her administration, in his bid to unseat Brownsberger, who co-led the push to kill her signature tax shift bill in the state Senate in late 2024.

Boston Mayor Michelle Wu-backed candidate Daniel Lander seeks to unseat longtime state Sen. William Brownsberger in the September primary. Boston Herald file photo // Courtesy Lander campaign

In a shot at Wu, former Mayor Marty Walsh has endorsed Brownsberger, who is also backed by Gov. Healey and Attorney General Andrea Campbell.

Lander, who supports Wu’s tax bill, has touted an endorsement from U.S. Sen. Elizabeth Warren, a mentor of Wu. He worked as a senior political advisor for Warren’s 2020 presidential campaign.

Lander has cast the race as trying to change the “broken” status quo of Beacon Hill, by trying to oust Brownsberger, whom he calls its “architect.”

Brownsberger is facing his first challenge since winning his Senate seat in a 2011 special election. He has touted his experience, and has been praised for his ability to work with other legislators “to get things done,” as Walsh put it.

Brownsberger, a Belmont Democrat, represents neighborhoods beyond the Hub. His Suffolk and Middlesex District seat includes Watertown, Belmont, as well as the Fenway and Allston-Brighton neighborhoods of Boston, and West Cambridge.

Suffolk District Attorney — Hayden vs. Rollins vs. Champion

A nasty Suffolk District Attorney’s race simmers in the long-standing vitriol between incumbent Kevin Hayden and his predecessor Rachael Rollins. A third candidate, Linda Champion, has sought to cast herself as a steady alternative.

Hayden and Rollins took swipes at each other over their past ethics lapses at a rowdy debate in Roxbury earlier this month.

Rollins resigned in disgrace from her post as the Massachusetts U.S. Attorney in May 2023 amid a federal ethics probe that found she abused her position by leaking confidential information that was damaging to Hayden and lying about it to federal investigators.

Candidates Rachael Rollins, Kevn Hayden and Linda Champion, left to right, listen as moderator Courtney Boston speaks during a Suffolk County District Attorney candidate debate forum,Thursday, at Hibernian Hall in Roxbury. (Mark Stockwell/Boston Herald)

Two damning federal watchdog reports found that Rollins leaked confidential Department of Justice information during her time as U.S. Attorney in an effort to influence the Suffolk DA’s race in favor of her preferred successor and fellow progressive, ex-Boston City Councilor Ricardo Arroyo.

Hayden won the 2022 Democratic primary over Arroyo and ran unopposed in the general election that year. He is seeking a second, four-year term.

Rollins claimed during the debate that she resigned as U.S. attorney not because of the federal ethics probe, but because she was receiving death threats, calling herself a “crime victim.”

She called the findings of the federal probe “allegations” while pointing to a 2024 state ethics violation Hayden was hit with related to that same primary race with Arroyo, for which he paid a $5,000 fine.

Rollins has faced a different scandal this time around, amid her bid to reclaim her old job as Suffolk DA.

Suspicious signatures out of Chelsea were flagged on Rollins’ nomination papers, a matter Rollins said she is looking into and AG Campbell said should lead to her removal from the ballot, if “she fraudulently got on the ballot.”

Hayden has been slammed by the Boston Police Patrolmen’s Association, over his decision to charge a city cop with manslaughter following a fatal police shooting of a carjacking suspect. The BPPA has endorsed Champion, a prosecutor who ran unsuccessfully for Suffolk DA in 2018, the race Rollins won.

The DA has also been criticized by community and elected leaders for choosing not to release the related police body camera footage before the homicide trial.

Champion said during the debate that both of her opponents are unfit for office.