Backing out isn't as bad as just breaking/ violating it, but yes, international reputation rests on a country keeping promises made in treaties. And in the US,

Backing out isn't as bad as just breaking/ violating it, but yes, international reputation rests on a country keeping promises made in treaties. And in the US, the supremacy clause of the Constitution (Article VI, Clause 2) states that ratified treaties are the "supreme law of the land," second only to the Constitution itself. The Supreme Court, in it's famous Holland ruling, clarified that this includes laws and policy that otherwise would be a State matter, like land rights.