March 2, 1966. An amendment to repeal the Gulf of Tonkin resolution is defeated in the Senate, 95-5. The amendment had been submitted by Wayne Morse, a Democrat from Oregon  who (along with Alaska senator Ernest Gruening) had been one of two No votes on the Resolution in 1964. According to Vice President Humphrey, LBJ didn’t hold his Vietnam position against Morse: 

“…But every Thursday Morse would get up in the Senate and say he was going to impeach Johnson over the weekend. And Johnson would still call him up and ask him to come over to the White House. he never mentioned his attacks.

"Because he knew that after Wayne’s attack on Thursdays, and this went on for months, years, Wayne would be back the next Monday and give a rip-roaring speech on the Senate floor about Johnson’s great domestic programs.

"Then it would come Thursday again, and Wayne would want to impeach him again. ”

– Hubert Humphrey, in Merle Miller, Lyndon: An Oral Biography. New York: G.P. Putnam’s Sons, 1980, p. 460. More on Wayne Morse here. Photo from Senate.gov.