According to the us constitution, which branch has the power to declare war?

The Congress has the power to declare war

1.  You write your federal representative or senator about your idea.

2. The bill goes to the House for action

3. Committees debate and edit the bill.

4. You write your state legislator about your idea.

5. The state Senate approves the bill.

Explanation:

The bill is first written by the representative of the senator. Then it is introduced to either the house or the senate. The house analyses the bill by conducting debates and then the bill is change, rebuilt, or sent back to the committee.  

In case everything looks good in the bill, it is then sent to the governor or the state legislator.  

State Senate reviews the bill and in case of any query questions the law writer and when convinced, it passes the bill