Goal of the game: You are a Political Party trying to control the 3 Branches of the Government. First control the States (Legislature). Next control the Supreme Court (Judicial). Then control the Presidency (Executive).
Roll and move to collect (purchase) States which increase the number of votes you receive towards the 280 required to win the game. When you control all the States of a Territory, you can start to add Support which will increase the income level for any State in that Territory.
Control the Supreme Court by appointing 5 of the 9 Supreme Court Justices. Appointment is scaled with the first requiring 50 votes and $500K, the 2nd 100 votes, 3rd 150 votes, 4th 200 votes and the 5th and final 250 or more votes. $500k must be paid in each case. Justices can be removed if your vote total drops below the required amount.
Controlling the Presidency requires 280 votes, 5 Justices and pay Five Million dollars to the bank. This is how you win the game.