Jerusalem mayor Nir Barkat will formally join Prime Minister Benjamin Netanyahu's Likud party next week in an apparent shift to national politics, Army Radio reported Thursday.The report cited an email from Barkat's headquarters that was sent to activists loyal to the mayor."Nir made a decision to declare his intention to join Likud on December 15," said the letter, which called on the activists to join the party in order "to help Nir achieve a central position in the leadership of the state."A Barkat associate responded that it was no secret that he supported Netanyahu and the Likud in the last two national elections. In the election before that, he backed Kadima."Beyond that, the rest is speculation," the Barkat associate said. "He has not decided yet whether to seek a third term as mayor of Jerusalem. He will decide in the next two years."