Gov. Arnold Schwarzenegger appealed to state lawmakers to "put party issues aside" as they consider his choice for lieutenant governor on Thursday.
The Senate and Assembly are scheduled to take up his nomination of state Sen. Abel Maldonado in back-to-back morning sessions.
Unless one of the chambers rejects the nomination, the 42-year-old Republican senator from Santa Maria will automatically take office as Schwarzenegger's backup until he leaves office next year.
Maldonado, who also is running for the seat in this year's election, goes before the state Senate with support from leaders of both parties.
Senate President Pro Tem Darrell Steinberg, D-Sacramento, and Sen. Bob Dutton, R-Rancho Cucamonga, have said they often disagree with Maldonado but think he is qualified to be the fill-in governor when Schwarzenegger is out of state. That is the main duty of the largely ceremonial post.
Dutton is set to take over as minority leader later this year.
Maldonado has less support in the Assembly.
In both chambers, Democrats are concerned that Maldonado could drop his previous opposition to a Schwarzenegger's proposal for offshore oil drilling. He would sit on the State Lands Commission, which decides such issues, if his nomination is confirmed.
Maldonado also angered many Republicans with his support last year for temporary tax increases to help balance the state's budget.
The lieutenant governor's post opened last year when Democrat John Garamendi won a seat in Congress.
Others running for the seat are concerned about facing an incumbent if Maldonado is confirmed. He intends to seek the Republican nomination in the June primary, and several lawmakers have said the seat should be left vacant until voters have their say.
Schwarzenegger called for legislators to approve Maldonado because he has taken a middle path between conservative and liberal lawmakers.
"We have to put party issues aside and politics aside," Schwarzenegger said Wednesday as he urged bipartisan cooperation on Maldonado's confirmation, efforts to create jobs and ways to close the state's $20 billion deficit. "I urge the Legislature to work with me on all of those things and do what is best for the people of California."
Schwarzenegger used an appearance on "The Jay Leno Show" in November to announce his nomination of Maldonado.