Article 2 section 2 of the US Constitution
"He shall have Power, by and with the Advice and Consent of the Senate, to make Treaties, provided two thirds of the Senators present concur; and he shall nominate, and by and with the Advice and Consent of the Senate, shall appoint Ambassadors, other public Ministers and Consuls, Judges of the supreme Court, and all other Officers of the United States, whose Appointments are not herein otherwise provided for, and which shall be established by Law: but the Congress may by Law vest the Appointment of such inferior Officers, as they think proper, in the President alone, in the Courts of Law, or in the Heads of Departments."
The Congress
Congress can
The president can make treaties, but Congress must ratify them.
Congress
No. The Senate alone votes to ratify treaties.
The Senate
The Senate.
US Senate
Congress can declare war (senate) and ratify treaties.
congress
Because the Senate must ratify treaties with a super majority.
It depends on the constitution, if any, and the legislation of the country in question.