Governor Arnold Schwarzenegger has declined to stop tonight’s scheduled execution of convicted murderer Donald Beardslee, denying a request for clemency and for a stay of the execution.

Beardslee has claimed mental impairment at the time of the murders. But in a short written the statement, the governor said that “nothing in his petition or the record of his case convinces me that he did not understand the gravity of his actions.”

The denial of clemency means that barring any last-minute involvement of the courts, Beardslee will be put to death by lethal injection at San Quentin just after midnight. (In an interesting aside, the governor’s staff refuses to say just where Schwarzenegger will be tonight, except to say he will be “available.”)

The governor’s staff says he spent part of the weekend reading the documents submitted by attorneys on both sides, as well as the recommendation of the state Board of Prison Terms, which was to deny clemency.

Beardslee, 61, was sentenced to death for the 1981 murders of two women. Schwarzenegger also denied clemency last year for death row inmate Kevin Cooper, whose execution was ultimately blocked by an appeals court.

No California governor has granted clemency since Ronald Reagan stopped the execution of a brain-damaged inmate in 1967.