It would be better to get a United Nations mandate for a mission to clear the Strait of Hormuz including Italian minesweepers, Defence Minister Guido Crosetto said Monday but stressed that he had to make a pragmatic choice on the issue.     "I was the first to speak about the need for a UN mandate," Crosetto said at the presentation of the book by centrist Azione leader Carlo Calenda.     "I'm absolutely certain it would be much better, but it could be blocked in the Security Council by anyone