John Dean, the former Nixon White House counsel, has a memo for White House lawyer Ty Cobb and the rest of President Donald Trump’s defenders as they enter 2018: believing the investigation and prosecutions will be over any time soon is “wishful thinking.” And, says the man who famously flipped and became the Watergate prosecution’s star witness in the process that helped take down Richard Nixon, no one in the president’s orbit should assume they’re prepared for everything that cooperating witnesses George Papadopoulos and Michael Flynn might be telling Bob Mueller, as they’ve done out of confidence from their own review or just out of public bluster. That’s the mistake Dean saw Nixon, H. R. Haldeman and John Ehrlichman make about him.