Senator Graham threatens subpoena on Trump wiretapping claim

By Doina ChiacuWASHINGTON (Reuters) - Republican Senator Lindsey Graham said Congress was ready to "flex its muscles" if FBI Director James Comey did not answer questions by Wednesday about any Russian ties to the Trump campaign or provide evidence of a wiretapping warrant for Trump Tower.Graham, in a series of television interviews, said he wasprepared to issue subpoenas for information on whether the Federal Bureau of Investigation received a warrant to tap Trump's phones during the 2016 presi