Sept. 1 (UPI) -- Sen. Ed Markey defeated Rep. Joe Kennedy III in a bid for his Senate seat during Massachusetts' primary elections on Tuesday night.
Markey, the longest-serving member of the state's congressional delegation, earned 54% percent of the vote to defeat Kennedy, the 39-year-old grandson of former Sen. Robert Kennedy and grandnephew of former President John Kennedy, who tallied 46%.
After winning Tuesday's contest, Markey is expected to be heavily favored to win the general election on Nov. 3.
Markey, 74, served in the House for 37 years before winning a special Senate election in 2013 to replace John Kerry, who'd left to become President Barack Obama's secretary of state. Markey was backed by Massachusetts Sen. Elizabeth Warren and New York Rep. Alexandria Ocasio-Cortez.
Though the two candidates agree on many policy issues, the contest was being closely watched as an indicator on whether Democratic voters will continue to express a preference for a new generation of party leaders.
Primaries were also held Tuesday in four of Massachusetts' nine congressional districts, including Kennedy's 4th District, where a crowd of seven Democrats are seeking the nomination for the seat.
Another Democratic contest saw Rep. Richard Neal, who's represented the state's 1st District since 1988, defeat Alex Morse, a 31-year-old mayor of Holyoke.
State officials expect as many as 1.3 million ballots will be cast -- many of which will be mail ballots, which are being used for the first time in the state's primary history.
Massachusetts official William Galvin said more than 768,000 Democratic ballots and 88,000 Republican ballots had already been received by Monday. The record for a primary is 900,000, set in 2006.
Voters may have to wait until Wednesday for results due to the high number of mail ballots, Galvin said.
"I'm hopeful that it's not going to delay the process in any extraordinary way, but it is more complicated," he told reporters Monday. "It is very cumbersome because we have a great amount of paper that's already been received."