Updated at 12:38 p.m.
Massachusetts U.S. Rep. Joe Kennedy III is not committing to an early debate about climate change with Sen. Ed Markey.
Kennedy is challenging Markey in next year's Democratic primary for Senate.
Shortly before Kennedy made his formal campaign announcement Saturday, Markey issued his debate challenge.
"I’m asking environmental groups in Massachusetts, who have shown the greatest commitment to fighting climate change, to sponsor this debate, and to establish a format that will provide the best opportunity for voters to hear from all of the candidates," Markey said in a campaign video.
A day later on a campaign stop in Springfield, Kennedy said he’s prepared to debate climate change and other topics, but said his campaign is just getting started.
“Look, it’s Day Two of a campaign," Kennedy said Sunday. "I expect to have a robust discussion of debate schedules with all the folks in this race, and look forward to going through that process, absolutely.”
In addition to Kennedy, two other Democrats have announced bids for the seat — labor attorney Shannon Liss-Riordon and businessman Steve Pemberton. The Markey campaign said both Liss-Riordan and Pemberton have accepted the senator's debate invitation.
Markey recently touted the endorsement of U.S. Representative Alexandria Ocasio-Cortez, who — along with Markey — introduced the so-called Green New Deal, a slate of proposals intended to tackle climate change.
Differences with Markey?
Asked for specific issues on which he differed with Markey, Kennedy said he's calling for the Senate to change its rules to prohibit the filibuster.
"I think that if you're going to implement a number of the big, progressive agenda items that I think many of us want to see across our country, including the Green New Deal, you need to end the filibuster," Kennedy said.
Markey, according to his spokeswoman Mara Dolan, said a decision on the filibuster would be premature. She said Markey wants to wait until after the 2020 elections so he can see "where [Democrats] are positioned."
Kennedy cited a few other differences with Markey, although their positions — at least now — may actually be aligned.
Kennedy said he's refusing to take campaign contributions from corporate political action committees. Asked to comment, Dolan said Markey has likewise decided to refuse donations from corporate PACs going forward.
Kennedy is also calling for a pair of changes that would require constitutional amendments: an end to the electoral college, and term limits for Supreme Court justices. Dolan said Markey is in agreement on both proposals.
Sam Hudzik contributed to this report.
