Two days after Italy’s highest court deemed unconstitutional a law granting Prime Minister Silvio Berlusconi immunity from prosecution, Mr. Berlusconi said he had no plans to step down. “I am the best prime minister ever,” he said at a news conference on Friday, Italian news media reported. “I am absolutely the politician most persecuted by prosecutors in the entire history of the world throughout the ages.” He said that he had spent “200 million euros on judges,” only to be corrected by associates, adding, “Excuse me, on lawyers.” Mr. Berlusconi’s Fininvest holding company was fined $1.1 billion last week for bribing judges in the 1990s. There are three cases pending against him concerning his business dealings.