Trump's decision is not yet final

Congressman last year advocated for arming Taiwan

Sources claim phone call could happen at later date if US president-elect agrees

Lai Ching-te seeks to strengthen cooperation on basis of 'close and friendly partnership'

Former U.S. senator and presidential candidate Bob Dole arranged for the phone call between Trump and Tsai

Taipei confirmed news of the call, the first of its kind since the U.S. severed diplomatic ties with Taiwan in 1979