The announcement caps a dizzying a few months for Murphy, the wife of Gov. Phil Murphy, who entered the race as a frontrunner, racking up endorsements and raising $3.2 million in six weeks, but watched her campaign stall as Rep. Andy Kim overtook her in the polls.
Murphy was running to replace embattled incumbent Bob Menendez who is facing federal corruption charges.
"Continuing in this race will involve waging a very divisive and negative campaign," Murphy, who pledged to do everything to defeat Donald Trump, said.
Murphy dropping out comes out on the heels of Menendez announcing he won't run in the Democratic primary, clearing the field for Kim. New Jersey has not elected a Republican to the Senate since 1972. Menendez has not ruled out a third party bid.
Kim was able to successfully hit Murphy on her past support for Republican candidates and turned his campaign into a referendum on New Jersey's controversial county line ballot system, where candidates endorsed by party bosses are grouped together in a favorable position on primary ballots, giving them a leg up on their opposition in 19 out of 21 New Jersey counties.
Murphy did not endorse Kim in her announcement. In a statement, Kim said he looks forward to working with Murphy.
"Unity is vital," Kim said. "We will continue our efforts to strengthen our democracy in New Jersey while we come together to stand up against the dangerous agenda pushed by Trump."
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