By Donald Shaw, Sludge. This story originally appeared in Sludge. It is republished here as part of DeSmog's partnership with Covering Climate Now, a global collaboration of more than 250 news outlets to strengthen coverage of the climate story.

Rep. Joe Kennedy III (D-Mass.), the grandson of former attorney general Robert F. Kennedy, has filed paperwork to challenge Sen. Ed Markey (D-Mass.), one of the Senate’s most progressive members and the chief sponsor of the Senate version of the Green New Deal resolution.