Signature of a treaty as a witness by a high-ranking official of a state that is not a party to an international agreement is a political rather than a legal act. It does not, in and of itself, make the state of the witness a guarantor of the performance of the treaty.
Witnessing an international agreement may reflect the involvement of the state represented by the witness in the negotiation or the promotion of the agreement and its concern that the treaty should be a success.
The United States has witnessed a number of international agreements. For example, the 1995 General Framework Agreement for peace in Bosnia and Herzegovina was witnessed by representatives of the Contact Group nations – the United States, Britain, France, Germany, and Russia – and the European Union Special Negotiator.
Similarly, the United States (Secretary of State Madeline Albright) witnessed the 2000 Agreement between the Government of the Federal Democratic Republic of Ethiopia and the Government of the State of Eritrea.
The United States (President Clinton) witnessed the 1994 Treaty of Peace between the Hashemite Kingdom of Jordan and the State of Israel.