Suffrage effected many American citizens in the 1780's. The law at the time dictated that only men who owned property could vote which caused only the upper class men to be able to vote. This caused the government to operate in their favor instead of the mass.
A constitution sets the duty and power of a government. The USA's constitution is set up in such a way that power is distributed between 3 different branches of government. This allows the government to have enough power to operate while making sure one branch can't over throw another.
Republicanism is support for a republic government which is a government. A republic government allows for the majority of people to be satisfied without having to get everyone's input. The creation of the US government followers republicanism since we vote in representatives (President, Congress, Senate) who will operate the government for us.