Question

Article One of the Constitution describes the powers of the

Answer 1

Congress.....the Legislative Branch

Answer 2

Thanks

Answer 3

Article 1- The Legislative Branch
Article 2- The Executive Branch
Article 3- The Judicial Branch

So the answer to your question is: Legislative branch, such as declaring war.

For more info or better understanding: http://en.wikipedia.org/wiki/Separation_of_powers_under_the_United_States_Constitution