Perry, a Republican who replaced President George W. Bush as governor of the U.S.' top death penalty state, rejected the bill 12 hours before it would have become law without his signature at 1 a.m. Monday EDT. 

He said he chose to veto the measure after several
'difficult and emotional days of decision-making,' and intense lobbying from both sides of the capital punishment debate. 

'Basically, this is not about whether to execute mentally retarded inmates. We do not execute the mentally retarded in Texas. It's about who makes the determination in the Texas judicial system,' Perry said at a news conference at the Texas State Capitol. 

Under the bill, judges -- and not juries -- would hear evidence of a capital murderer's mental abilities to determine whether they are retarded in the eyes of the law. If so, the convicted killer would face a maximum penalty of life in prison. 

Currently, Texas juries decide whether a capital murderer should be put to death during the sentencing phase of a trial. 

Defendants are already allowed to present evidence
that they could not determine right from wrong or that they are insane, safeguards which Perry said he took into account in his decision. 

UNDERMINING JURY SYSTEM? 

The bill would have undermined the Texas jury system, Perry said. 'This tells the citizens of this state 'We do not trust you to get it right,'' said Perry, surrounded by two dozen relatives of murder victims and prosecutors. 

Both groups adamantly opposed the bill. Perry said he would have signed an alternate bill that would have let juries determine a killer's mental status. 

Texas would have been the 16th of the 38 states that impose the death penalty to enact such a law. The Texas bill was like one Florida Gov. Jeb Bush, President Bush's brother, signed into law last week, in that it left the determination of retardation in the hands of judges. 

The issue is a key one in Texas because the state has come under fire for its high number of executions and because of the case of Johnny Paul Penry, a 45-year-old man with a low IQ who was sentenced to die for a 1979 murder. 

Penry came within three hours of execution in November before the U.S. Supreme Court ordered a stay. On June 4, the nation's highest court overturned his death sentence and ordered a new punishment trial on the grounds that his jury received 'illogical' instructions. 

Perry flatly rejected claims by State Sen. Rodney Ellis, a Houston Democrat, that Texas has executed six mentally retarded killers. 'Today, I wanted to clearly lay out that we do not execute the mentally retarded in Texas. That is a fallacy,' he said. He recounted details of their six purportedly retarded killers' crimes during the news conference. 

'They don't fit the image of the loving, impaired individuals many of us know with mental retardation,' Perry said. 

Texas has executed eight people this year and 247 since capital punishment resumed in the state in 1982, six years after the U.S. Supreme Court lifted a ban on executions.