The Senate.
Congress
In the US, only the Federal Government can do this; states cannot do this individually.
it is the supreme authority of senate to ratify treaties with foreign nations by a majority of vote.
Congress can
No. According the US Constitution, only the Federal Government has the ability to make, sign, and ratify treaties with foreign countries. From the Iraqi perspective, there is no issue.
The Senate.
The legislative branch is responsible for the approval and ratification of treaties.
Diplomats negotiate treaties, government officials sign them, and national legislatures ratify them.
States cannot enter into treaties independently; only the federal government has the authority to negotiate and ratify treaties with foreign nations. This power is reserved for the U.S. Constitution, specifically in Article II, Section 2. However, states can engage in agreements or compacts with each other or with foreign entities, but these typically require congressional approval to ensure they do not conflict with federal treaties or laws.
To ratify means to approve and make binding an agreement that has been made by someone not able to make it binding himself. Typically, an agreement made between countries can be made by representatives of the countries but it will need to be ratified, i.e, accepted and approved by the countries' governments before it become a legally binding agreement.
Me
The Legislative Branch can ratify treaties; The Senate approves Presidential Appointments