NEW YORK, March 6 (Reuters) - Syria's envoy to the United Nations says it's time for the United States and other Western powers to accept that President Bashar al-Assad is here to stay, and to abandon what he suggested was a failed strategy of trying to split the Middle East into sectarian enclaves.Speaking to Reuters on the eve of the fourth anniversary of the Syrian war, Assad's long-serving U.N. ambassador Bashar Ja'afari said his president was ready to work with the United States and others to combat terrorism in the Middle East."We don't want any vacuum in the country that would create chaos such as happened in Libya and Iraq and ... Afghanistan," he said. "President Assad can deliver because he is a strong president. He rules over a strong institution, which is the Syrian army. He has resisted pressure for four years.""He is the man who can deliver any solution," he added.