[nickpsecurity]

It wouldn't understand any key issues. Foreign leaders would trick it into bad negotiations with Q&A schemes. It couldn't read the body language of opponents in negotiations. Being President, not Legislature, it couldn't meet its stated goals because nonprofit set it up to fail. Little known AI developers and admins that build and run Watson would also control our country via proxy with difficulty proving their effects. One may even install Global Thermonuclear War.

All in all, this is a terrible idea for all kinds of reasons that have no connection to the false idea that Watson is intelligent. ;)