Johnson defends Trump’s rigged elections claim — says it’s 'impossible to prove'

President Donald Trump just received a public assist from House Speaker Mike Johnson in his unsubstantiated claims that California’s elections have been stolen — but Johnson himself admitted that Trump’s claims are “impossible to prove.”“I'm not saying it's rigged,” Johnson told CNN’s Manu Raju on Monday. “I'm saying it stinks to high heaven. And everybody…