What makes you think he isn't? Covering all bases...
I suspect he might also be laying the groundwork for an effort to first, marginalize the justices who vote against him, with a view toward eventually dissolving the Supreme Court and the rest of the judiciary once he becomes absolute ruler. I still suspect he's going to try to stay in office after his term expires, or he and his party are going to ensure that his successor will be a commie dictator.