Final answer:
States enter into congressional-executive agreements or compacts with foreign nations and other states with the consent of Congress, which are approved by a simple majority in both houses.
Step-by-step explanation:
Agreements that states enter into with both foreign nations and other states with the consent of Congress are known as congressional-executive agreements or compacts. Unlike treaties which require a two-thirds vote in the Senate, congressional-executive agreements are approved by a simple majority in both the House and Senate. This approval process is necessary for certain types of agreements that may commit the United States to make payments or affect domestic law. Executive agreements are another form of international agreement negotiated by the president and enforceable as long as they do not conflict with current domestic law, and do not generally require congressional approval.