Oregon Revised Statutes Procedure in Civil Proceedings § 15.350

(1) Except as specifically provided by ORS 15.320, 15.325, 15.330, 15.335 or 15.355, the contractual rights and duties of the parties are governed by the law or laws that the parties have chosen. The choice of law may extend to the entire contract or to part of a contract.

(2) The choice of law must be express or clearly demonstrated from the terms of the contract. In a standard-form contract drafted primarily by only one of the parties, any choice of law must be express and conspicuous.

(3) The choice of law may be made or modified after the parties enter into the contract. Any choice of law made or modified after the parties enter into the contract must be by express agreement.

(4) Unless the parties provide otherwise, a choice of law or modification of that choice operates retrospectively to the time the parties entered into the contract. Retrospective operation under the provisions of this subsection may not prejudice the rights of third parties.