The Boston Globe endorsed Sen. Ed Markey (D-Mass.) in his primary battle against Rep. Joe Kennedy (D-Mass.), calling him a “progressive champion with a solid track record.”

The paper’s editorial board’s endorsement that came late on Monday pointed to Markey’s calls for environmental advocacy stemming back to the 1980s and painted him as one of the original champions of the environment.

“Decades before CNN hosted its first town hall for presidential candidates devoted to climate change, and decades before Greta Thunberg, the Swedish teenage activist, was named Time magazine’s 'Person of the Year,' Markey worked to make the air we breathe cleaner and to stave off the catastrophic heat waves, droughts, and rising seas poised to displace millions of people around the world," the board wrote.

Additionally, the board argued that Kennedy had not made a "persuasive case" for voting Markey out of office, saying he “lacks the chops and track record“ on climate issues.  

The endorsement comes after the Globe reported on Monday that Markey, who has served in Congress since 1976, spent the least time in the Bay State than any other member of its congressional delegation.

Markey has defended his travel schedule, saying he has delivered on his campaign promises in Washington. Markey and Kennedy will go head-to-head on Sept. 1 in the Democratic Senate primary.

Kennedy leads Markey by an average of 9 points, according to the RealClearPolitics average of the polls conducted ahead of the primary.

The 39-year-old congressman announced last year that he is challenging Markey in the state’s Senate primary. Kennedy is the grandson of former Attorney General Robert F. Kennedy and says he is pushing for a generational change in Washington.

Markey has touted his progressive credentials throughout the campaign, including co-authoring the Green New Deal with progressive Rep. Alexandria Ocasio-Cortez (D-N.Y.).