(a) Prohibited Uses. Evidence of the following is not admissible on behalf of any party, when offered to prove liability for, invalidity of, or amount of a claim that was disputed as to validity or amount, or to impeach through a prior inconsistent statement or contradiction:
(1) furnishing or offering or promising to furnishor accepting or offering or promising to accepta valuable consideration in compromising or attempting to compromise the claim; and
(2) conduct or statements made in compromise negotiations regarding the claim, except when offered in a criminal case and the negotiations related to a claim by a public office or agency in the exercise of regulatory, investigative, or enforcement authority.
