Haven't you noticed which side John Roberts has been voting with lately? He's a never Trumper that is out to destroy Trump and his presidency, if you ask me. Just like all the rest of the Bush clan.
Roberts votes have been self serving. His vote on this will also be self serving. But, Roberts does not want to be a Chief Justice of a 15 member Supreme Court which will happen if the Democrats win the White House and the Senate. He will vote with Trump on this one.