Why didn't the united states immediately annexed texas when it had the chance?

The united states avoided immediately annexing texas to avoid upsetting the balance between free states and slave states established by the 1820 Missouri Compromise

You for the free points

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.