President Uhuru Kenyatta implored Senate Speaker Kenneth Lusaka to join Azimio la Umoja instead of Ford Kenya.
But Lusaka said he told Uhuru it would be difficult to go against the tide.
"I told the President I didn't want to go through what I went through in 2017 when I vied on the Jubilee ticket against the wishes of the people resulting in my loss," he said.
Lusaka on Thursday spoke for the first time about the behind the scenes events that informed his political move.
He is seeking to recapture the Bungoma governor seat he lost in 2017 to Wycliffe Wangamati, who ran on the Ford Kenya ticket.
This time around Lusaka is in Ford Kenya, while Wangamati is seeking reelection on the DAP-K ticket.
Ford-K is one of the parties supporting the Kenya Kwanza Alliance, which is fronting Deputy President William for President.
Wangamati's DAP-K is one of the parties supporting Azimio and its presidential candidate Raila Odinga, and is backed by the President.
"It is true the President really pleaded with me to either join Azimio or not run and maintain my position as Speaker of the Senate. But I, with lots of respect, told him that I have to listen to the ground," Lusaka said during a Capital FM talk show.
Lusaka said his decision to join Ford Kenya was to secure his future.
Despite his move, however, Lusaka said he is still good friends with Uhuru.
Lusaka said he told Uhuru that the majority of elected MPs in Bungoma were allied to Ruto and it would be hard to go against that tide.
He said Ford-K is very popular in Bungoma. "Every politics is local and though it was a very hard decision, I had to finally decide," the Speaker said.
Asked whether he has been partisan as Senate Speaker by always defending the Executive, Lusaka said he has been impartial as required of him by law.
"I always worked as an impartial Speaker. The problem is in every debate the loser will always want to blame the referee for the loss," he said.
Lusaka said it was not his role to defend the government or opposition agenda, adding that those were the roles of majority and minority leaders.
He also defended the role of the Senate, saying without it devolution would be killed.
"Those saying the Senate has no role don't actually know what they are saying because we are the fathers of devolution," Lusaka said.
He said the Senate should be protected because it protects devolution.
Edited by Josephine M. Mayuya
