John Fetterman Endorses Andy Kim in High-Stakes New Jersey Senate Primary

Senator John Fetterman of Pennsylvania is endorsing Representative Andy Kim of New Jersey in the primary to unseat Senator Bob Menendez, the embattled veteran Democrat who is under indictment in a federal corruption case, taking the rare step of wading into a high-stakes intraparty fight to oust a colleague.

Mr. Fetterman, the harshest Democratic critic of Mr. Menendez in Congress, who has repeatedly called on him to resign, is the first sitting senator to endorse any candidate in the race. In an interview, he explained his decision to intervene in a primary to take out a fellow sitting senator, stating bluntly that “anything would be an upgrade over Menendez.”

Mr. Kim, a three-term congressman representing a southern New Jersey district that former President Donald J. Trump won twice, is running for the seat against Tammy Murphy, the first lady of New Jersey and a first-time candidate who is a former registered Republican. Ms. Murphy has locked up much of the institutional support in a state where county leaders hold enormous power in primary campaigns, but has struggled to gain grass-roots traction.

Mr. Kim is leading by double digits in some recent polls.

In an interview, Mr. Fetterman said that he was “enthusiastic” about Mr. Kim and that Ms. Murphy’s political background — she changed her party affiliation from Republican to Democrat only in 2014 — gave him pause.