In this form of government only a few people can rule

Oligarchy,

Explanation:

Oligarchy is a system of government   in which power rests with a small number of people. These people are distinguished by nobility, wealth, family ties, education or corporate, religious or military control. Such states are often controlled by families who typically pass their influence from one generation to the next, but inheritance is not a necessary condition for the application of this term.

because it took place after the war of 1812 had come to an end.