The race has pitted incumbent Sen. Ed Markey, the longest-serving member of the Massachusetts congressional delegation, against challenger Rep. Joe Kennedy III, the grandson of the former attorney general and Sen. Robert F. Kennedy (D-N.Y.).
The campaign has turned deeply personal in recent weeks, with the Kennedy clan being drawn into the discourse.
And while the battle has been portrayed in much of the news media as a contest between who can be the most progressive, strategists say it will ultimately come down to the candidates’ records.