nationalism
Bolivia, Peru, Chile, Belgium
There are too many countries and too many wars to give you an answer. You need to pick a country and a war or a time.
It was ground artillery wars that led to the construction and use of trenches in combat. These trenches provided military members with an adequate area to position themselves against opposing forces that took them out of the direct line of hand artillery.
The surrender led to the end of war with the Soviet. It also helped to end other Germany wars in Denmark, Holland and northwest Germany.
The build-up of the new Confederate States Army, and their challenge to Fort Sumter, a tiny island garrison in Charleston Harbour, which they declared to be Confederate territory.
nationalism
crack cocaine
The expansion of Spanish Empire led to Latin American wars of independence from Spain. It made territory much larger.
sacaguia
The Peninsular Wars, when France led by Napoleon Bonaparte invaded Spain and Portugal.
The tradition which weakened the Carolingian Empire was the partition of the empire among the sons of the emperor. This led to wars between the sons over territory, which was often also joined by other relatives.
The plague, and wars.
Meriwether Lewis.
Rome's victory in the Punic wars led to the diffusion of Roman culture, influence, laws and customs throughout the Mediterranean area.
They invaded other countries to gain new territory
Sparta and Athens.
Gorbachev