Which branch of government has the power to "declare war"?

executive

Legislative

judicial

Legislative branch of the government has the power to declare war.

Explanation:

The legislative branch includes Congress and legislative branch agencies. According to the War Power clause (Article I, Section 8, Clause 11) the power to declare war vests in congress. So far congress declared 5 wars by exercising the constitutional power to declare war.

American-Mexican War, World War-I, World War-II, American-Spanish War, the war of 1812. This power is given to congress rather than the president because he may exercise this power for his greed and can act like a dictator.