By Steve Scherer
ROME (Reuters) - Silvio Berlusconi's allies reacted angrily on Friday after Italian President Giorgio Napolitano left the center-right leader, who risks being ejected from parliament after a tax fraud conviction, off a list of new lifetime senators.
Napolitano had been pressed by members of Berlusconi's People of Liberty party (PDL) to grant their leader the honor bestowed on former heads of state and distinguished personalities in the arts and sciences.
But in a move that sends a clear political message to Berlusconi that he will receive no special treatment, Napolitano kept him off a list of four life senators named just a week before voting starts on whether to strip Berlusconi of his parliamentary seat under a law passed last year.
The appointees enjoy the full powers and privileges of being a lawmaker for life - including some legal immunity - meaning he could continue to wield influence after being found guilty and sentenced to four years of house arrest or public service that was commuted to one year.
The parliamentary committee begins its deliberations on September 9 but the decision has to be approved by a vote in the full chamber.
Berlusconi's allies have threatened to bring down the government they support along with Prime Minister Enrico Letta's center-left Democratic Party if the PD votes to oust him, as it has said it will.
"I'm very disappointed and profoundly sorry that the only one who should have been nominated a senator for life - Silvio Berlusconi - was not," Daniela Santanche, an adviser to the center-right leader, said in a statement.
"Without taking anything away from the four new life senators, I do not think they measure up to Berlusconi."
Friday's nominees were architect Renzo Piano, one of the creators of the futuristic Pompidou Centre in Paris and the Shard skyscraper in London, and Nobel Prize-winning physicist Carlo Rubbia.
Claudio Abbado, former director of the Berlin Philharmonic Orchestra, was another of the nominees along with a 50-year-old specialist in stem cell research, Elena Cattaneo.
There have been vacancies for the positions for some time after the deaths of some incumbents, making the timing of the unexpected appointments just ahead of the panel on Berlusconi even more significant.
Napolitano defended his choices in a statement sent immediately after the nominations were announced, saying all would make "highly significant" contributions "in absolute independence from political party influence".
Berlusconi was convicted of tax fraud on August 1, throwing Italian politics into disarray.
In addition to the tax fraud case, Berlusconi is fighting a seven-year jail sentence for paying for sex with an under-aged prostitute and abusing his office to cover it up.
Seven-times Prime Minister Giulio Andreotti, who died earlier this year, was a life senator while on trial for colluding with the Sicilian Mafia. He was eventually acquitted, but his position helped shield him from arrest during the proceedings.
Just six years ago it was common for then-Prime Minister Romano Prodi to muster the votes of life senators to keep his government on its feet during delicate votes because of his narrow Senate majority.
"I would not like to see these nominations take on the importance of the life senators had for the Prodi government," said Roberto Calderoli, vice president of the Senate and a member of the Northern League.
Napolitano appointed former Prime Minister Mario Monti a life senator in 2011, boosting his political status and opening the way for Monti to form an emergency government to save Italy from a Greek-style default when a discredited Berlusconi resigned.
The nominations bring the total number of life senators to six alongside Monti and former President Carlo Azeglio Ciampi.
(Additional reporting by James Mackenzie; Editing by Alison Williams)