IT’S BEEN HARD to find much daylight on issues between Ed Markey and Joe Kennedy as the liberal lawmakers match each other measure for measure on one progressive platitude after another. But give them credit for trying.

Taking swings that amounted more to wild flailing than surgical strikes, the Democratic primary contenders for US Senate each took stabs at muddying up the other’s liberal bonafides in their second debate in as many weeks. 

After being asked about his vote for the 1994 crime bill, which has come in for broad criticism in recent years, Markey turned the tables to Kennedy’s criminal justice background. In Markey’s telling, Kennedy didn’t simply work at one point as a prosecutor under Republican District Attorney Michael O’Keefe on Cape Cod, he worked for “the most conservative Republican right-wing district attorney in Massachusetts in a generation.” 

Markey, who is defending the Senate seat he won in 2013 against a challenge from the four-term congressman, said after the debate that Kennedy’s past work under O’Keefe “goes to his judgment, especially as we look at all the people who are protesting across our country, our state on the question of justice right now.”  

While Markey reached back a decade in his 39-year-old opponent’s record to question his progressive credentials, Kennedy set the wayback machine to Boston’s school busing conflict of the 1970s, charging that when Markey, who is now 73, first entered office “he actually opposed the integration of the Boston public school system.”

Race and criminal justice issues dominated the start of the debate, held exactly two weeks after the May 25 killing of George Floyd in police custody unleashed ongoing protests across the country against police brutality toward blacks. 

Jumping on the calls to dial back the reach of police departments, both candidates said they would support shifting some police resources to other programming. 

They also were in sync in opposing congressional term limits, supporting abolition of the Electoral College and the filibuster, and supporting tribal casino rights for the Mashpee Wampanoag in Taunton and Aquinnah Wampanoag on Martha’s Vineyard. 

Both also said they would support extending benefits to undocumented immigrants who have been sidelined from work by the pandemic. 

Markey and Kennedy both managed to split the difference or dance around two questions. 

On the call by New Bedford leaders to move a National Oceanic and Atmospheric Administration fisheries science center from Woods Hole to the South Coast city, the candidates said it should be possible to have NOAA facilities in both locations. But Markey may have nosed out a win in that round of working to please all parties. “I would throw in UMass Dartmouth as well,” he said. 

Asked about the restrictions on gatherings that people have been forced to observe while mass protests have unfolded across the country, Markey said it would be irresponsible to hold gatherings where people don’t maintain distance. “At the same time, it would be irresponsible not to be out in the street,” he said. 

Reflecting on the thousands of people who gathered last week in Boston’s Franklin Park to demand long overdue changes, Kennedy said, “I’m not going to call that irresponsible.” 

The candidates revisited, but didn’t revise, their positions on campaign spending in the race.   

Kennedy has called on Markey to agree to a “People’s Pledge” to discourage spending by outside super PACs in the race. Markey agreed to a similar pact in his 2013 Senate race, in which candidates pledged to donate to charity half of any amount spent on their behalf by outside groups. 

But he said this time he would only agree to a modified version that would allow outside spending from progressive groups sending a positive message about a candidate. Kennedy has called the idea unworkable, questioning who would make a ruling on whether spending passed that test. 

A super PAC affiliated with the advocacy group Environment Massachusetts announced last week that it would spend $200,000 to promote Markey over the coming weeks, drawing a sharp rebuke from Kennedy. A group of Kennedy backers said they were prepared to start their own super PAC, but Kennedy has urged them not to do so. 

“I know nothing about this, I didn’t ask for it, and we don’t want it, we don’t need it. We need to, as Democrats, reject dark money; we need to reject super PACs,” Kennedy said in a Facebook video post on Friday.  

Kennedy enjoys a big fundraising advantage at this point, with $6.2 million on hand as of the March 31 quarterly filing compared with $4.2 million that Markey reported. 

Kennedy launched a $1.2 million ad buy last month. Markey has yet to begin advertising. His campaign manager, John Walsh, said recently that Kennedy’s early spending suggests he’s worried that the lead he appeared to enjoy in early polls is shrinking. 

Much of the candidates’ campaigning since mid-March has been confined to Facebook sessions and other virtual communication with voters. 

In another sign of ways that the coronavirus pandemic has upended almost everything, Monday night’s forum may earn at least a footnote in political history as a debate for a US Senate seat that was held in another state. The candidates squared off at the Providence studios of television station WPRI after original plans for the debate in front of an audience at the University of Massachusetts Dartmouth had to be scrapped.