Answer:
The United States President can not declare a war or even fund a war without the vote of Congress.
Explanation:
The constitution allows power to be distributed accordingly to the three arms of Government in the central or National Government and this include how war powers are distributed.
According to the Constitution of the United States of America, in the eight section of Article I, the congress that is the legislative arm of the Government are given powers to declare war through votes.
Although, there has been many interpretation of this section of the Constitution, many cases has occured in which the President has to declare war without the consent of the Congress and they (Presidents) do this for different reasons for instance, when Harry Truman was the President, without seeking consent from the congress he sent soldiers to Korea.