Longtime incumbent Bill Galvin, who has served as the secretary of the Commonwealth since 1995, and his challenger, Boston City Councilor Josh Zakim, squared off during the first and only scheduled televised debate on Greater Boston Tuesday.

During the half-hour debate, the two traded a number of barbs, with Zakim calling out Galvin for failing to institute weekend voting in the decades he's been in office and for deciding to hold the primary on Sept. 4, the day after Labor day.

“After 24 years in office, the fact that we don’t have early voting or weekend voting at this point in time is a responsibility of the secretary of state,” Zakim told host Jim Braude. “He should have been advocating for that.”

Galvin, whose role is to oversee state elections, defended his decision to hold the primary on Sept. 4, saying that he had no good options because the day either conflicted with Jewish holidays or the start of school. Zakim charged that the decision was "irresponsible" and advocated that Galvin should have taken advantage of the law's flexibility and allowed a weekend primary to take place.

“We have advance weekend voting with early voting, but I don’t think a weekend necessarily is going to result in a higher turnout,” Galvin countered. “In fact, to do that for an exceptional thing like the primary, I think would diminish it.”

Throughout the campaign, Zakim has tried to brand himself as the more progressive candidate with a focus on access to voting. He’s pointed to the state’s abysmal voting turnout as a sign of his opponent’s shortcomings.

Galvin argued that he has pushed for early voting. “Every major progressive change that has occurred in Massachusetts election laws have come about because of me,” he said, pointing to automatic voting registration and early voting as examples. “That would not have happened without my advocacy,” he said.

Zakim shot back saying, “For Bill to say that he has been a proponent of every progressive electoral reform is false.”

“I’m tired of listening to misstatements of statistics,” Galvin said listing his accomplishments. “We have a great turnout in Massachusetts.” A recent assessment by the MIT Election Data Science Lab rated the state as eighth best in the nation in part because of registration and turnout.

Even though both support same-day voter registration, Zakim criticized the secretary for being a “recent convert.”

“I have never seen you at a hearing ever for same-day or for anything else,” Galvin said turning to Zakim.

“Well I haven’t seen you at our city council discussions on the same topic,” Zakim said.

Galvin cut him off by saying, “The city council has nothing to do with making law. I know it’s a fantasy down there that you do, but you don’t.”

Both candidates accused each other of political distractions. More personal attacks came when Galvin criticized his opponent for failing to vote in the 2004 and 2006 primaries. Zakim, 34, defended himself saying that he was in college out of state in 2004.

In Massachusetts, the secretary of the Commonwealth is elected every four years to oversee elections, the public records division and historical commission, among others. The secretary of the Commonwealth’s office also makes it so that the public can access public information — like employee’s salaries. For instance, the secretary’s salary in 2017 was $146,525.77.

Galvin, who was sworn into the office in 1995, pledged at the time to "seek to open as wide as possible to meaningful participation by citizens the processes that affect our daily lives."

Zakim has served as a Boston city councilor representing Back Bay, Beacon Hill, Fenway, Kenmore Square, Mission Hill, Audubon Circle, and the West End since being elected in 2013. At the party’s convention in June, Zakim won the party’s endorsement.

Whichever candidate wins the Democratic primary on Sept. 4 will end up on the general election ballot in November against the Republican candidate, Anthony Amore.