Federalism is best defined as a principle of
government that
(1) divides power between the central government
and state governments
(2) includes a system of checks and balances
(3) allows the states to nullify national laws
(4) places the most power in the hands of the
legislative branch

Federalism is best defined as a principle of government that "(1) divides power between the central government and state governments" although it varies slightly. 

Assemblies do not have written codes of laws. laws are matters for magistrates and courts, not assemblies. codes of law are things such as civil law, criminal law, and constitutional law. what assemblies have are procedures regarding debating, voting and other business they might carry out.  also note that rome had three assemblies: the assembly of the soldiers, the assembly of the tribes, and the plebeian councils.