By Gavin Jones
ROME (Reuters) - Center-right leader Silvio Berlusconi, who left Italy's political limelight after heart surgery, has returned to the fray this week trying to defeat Prime Minister Matteo Renzi's planned constitutional reform.
In his first television interview since June, the 80-year-old media tycoon told his own Canale 5 channel on Tuesday evening the reform was "dangerous" and had to be blocked to prevent Renzi becoming "the master of Italy and the Italians."
On Wednesday, after meeting heads of other center-right parties, he said it "would solve none of Italy's problems" and was being used by Renzi to divert attention from "the economic failures of his government."
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The reform, which goes to a national referendum on Dec. 4, aims to reduce the role of the Senate and cut the powers of regional governments.
Renzi says it will increase government stability and speed up lawmaking. Opponents say it will make Italy less democratic and complicate the legislative process.
The great majority of opinion polls over the last month put the "no" camp ahead, but with many voters still undecided, the margin remains narrow.
Berlusconi, who had an aortic valve replaced on June 14 after what his doctors said was a life-threatening cardiac disorder, headed four Italian governments between 1994 and 2011.
He has lost much of his political clout since being barred from office following a 2013 conviction for tax fraud, but his Forza Italia (Go Italy!) party is still backed by around 12 percent of Italians, according to opinion polls.
These votes could be vital in the referendum as polls show Forza Italia supporters are particularly undecided, with as many as 40 percent attracted by Renzi's proposals.
Berlusconi negotiated with Renzi in drawing up the reform and originally voted for it in parliament, only to withdraw his backing after Renzi refused to settle on a mutually agreed candidate for national president in 2015.
It remains to be seen how strongly Berlusconi will campaign ahead of the referendum. So far, his three television channels have been far from hostile to Renzi, prompting irritation among Berlusconi's allies who suspect he may be more concerned about defending his business interests than sinking the government.
U.S. President Barack Obama backed Renzi in the referendum battle on Tuesday, but said the Italian leader should stay in office even if he loses the vote.
Renzi used to promise he would stand down if the referendum is rejected, but he has stopped repeating this pledge over the last two months, leaving some doubt about his intentions.
(Reporting by Gavin Jones; Editing by Tom Heneghan)