Hope this helps
The veto allows the President to “check” the legislature by reviewing acts passed by Congress and blocking measures he finds unconstitutional, unjust, or unwise. Congress's power to override the President's veto forms a “balance” between the branches on the lawmaking power.
Voting rights I believe were restricted in that only one party the Socialist party was allowed. Some socialist countries at least where power was obtained by revolution in the world, like the Soviet Union or in Cuba had/have a one party system but still have democratic votes for various things, whereas more recently, socialist governments have come to power through the ballot box in countries like Venezuela or Bolivia.
The three main groups probably have been the British, the Boers and the Zulus
