You become the leader of a masterful political conspiracy that will utterly reshape the government of the country of your choice, implementing any and every change to its laws and governance that you desire.
but
No-one will ever know you were responsible. History will remember someone entirely different, perhaps one of your co-conspirators, as having masterminded the affair. No amount of investigation can trace any involvement you had in the conspriacy, and if you attempt to tell anyone, no-one will believe you.