The british government declared war as Hitler was not keeping his promises ans was trying to take over Europe, and had already seized Poland and most of Czechoslovakia and many other European nations.
Actually, Hitler invading Poland was the official start of WW2 recognized by most historians. Hitler had "annexed" Austria and seized most of Czechoslovakia
The Legislative Branch of government can declare war, or more specifically, Congress.congress.
How did the British government try to eliminate opposition from the people who were opposed to World War 1?
The power to declare war is a power that belongs to Congress.
The national government declares war.
This question was put into the categories of World War 1 and World War 2. The answer is that the US did not declare war in either war for the reason that the Germans threatened to sink all ships in British waters. World War 1: President Wilson chose to declare war on Germany in World War 1 when he learned from the Mexican Government that the Germans wanted to attack the US through the US borders and Gulf of Mexico. World War 2: President Roosevelt declared war after the Japanese bombed the US Naval ships and planes in Pearl Harbor on December 7, 1941. They became officially involved in the European Theater of Operation once Hitler declared war on the USA.
The British Empire
One Constitutional power specifically delegated to the federal government is the power to declare war.
In the U.S., the legislative branch of government is responsible, and has the constitutional powers, to declare war.
The British North Americans
In the United States government, Congress has the power to declare war on other nations.
The Queen
to declare war