The Republicans will look to use this as an opportunity to attack the Senator as she mulls the possibility of running for president in 2020.
Sen. Elizabeth Warren (D-Mass.) is set to square off against Republican Geoff Diehl, who was President Trump’s campaign co-chairman in Massachusetts, in the state's Senate race.
Diehl, a state representative, emerged the winner in the deep-blue state's Republican primary, The Associated Press projected. He won with 55 percent of the vote, defeating wealthy business executive John Kingston and Beth Lindstrom, a former aide to Gov. Mitt Romney (R).
Warren, who faced no primary challenger, is the favorite to win a second term in November.
Trump lost Massachusetts by 27 points in 2016. The Massachusetts congressional delegation consists entirely of Democrats, though the state has a popular Republican governor, Charlie Baker, who’s also expected to win reelection this fall.