Kennedy challenges incumbent in Senate primary

Massachusetts Democrats on Tuesday will decide whether they want to position a young member of the Kennedy family to be their choice for the U.S. Senate or stick with their incumbent, who has been in Congress for decades fighting to tackle climate change and reduce nuclear weapons proliferation.

This primary election pits 39-year-old Representative Joe Kennedy III, the grandson of Senator Robert F. Kennedy, against 74-year-old Senator Ed Markey, who has spent over 40 years in the House of Representatives and Senate.

And Tuesday's race also will test the clout of Alexandria Ocasio-Cortez, who's thrown her support behind Markey, and House Speaker Nancy Pelosi, who's backing the young Kennedy.

Kennedy presented his closing argument on Monday by taking a swipe at Markey's age, saying change will not come "by entrusting our future to the same people who built our past."

Ironically, Markey has resonated with young voters. On Sunday he reminded them he co-authored the "Green New Deal" to lower carbon emissions causing climate change, tweeting, "The fight for a livable future is a youth movement.

As the junior senator from Massachusetts, Markey has had to labor in the shadow of the state's better-known senior senator, Elizabeth Warren.

Whoever wins this Senate primary will be well positioned to win the November general election in a state that historically sends Democrats to the Senate.