Donald Trump tweeted unsubstantiated claims that Barack Obama had ordered the FBI to tap the phones at Trump Tower. He offered no evidence to support his claims. White House press secretary Sean Spicer says on Monday that there is ‘substantial reporting’ that merits congressional investigation. But former director of national intelligence James Clapper says Trump’s claims are untrue. Republican senator Marco Rubio says the White House must account for Trump’s allegations. And House Democratic leader Nancy Pelosi says Trump’s ‘smear’ is an authoritarian tactic