If you mean Bob Menendez , he did resign in 2024 after his corruption conviction, effective August 20, 2024. His resignation temporarily reduced the Senate Democratic majority until New Jersey’s governor appointed a replacement to finish the term.

What that meant

  • His seat became vacant. Governor Phil Murphy had the power to appoint an interim replacement for the remainder of the term.
  • The Senate avoided an expulsion fight. Before he resigned, Senate leaders had been weighing expulsion, which would have required a two-thirds vote.
  • There was a short-term partisan effect. Reuters reported that his resignation briefly lowered the Democratic Senate majority to 50-49 until the replacement was seated.

If you meant “what happens if a senator resigns” generally

  • The seat becomes vacant.
  • The state’s governor usually names a temporary replacement, depending on state law.
  • A special election or the next scheduled election then decides who fills the seat long term.

If you want, I can also explain what would happen if he had refused to resign or how New Jersey’s replacement process works.