Originally Posted by rustykettel

It's not specifically about policy, but how to determine what is the MSC under the IATA rule (when that applies, either as a non-US origination/termination or when the first marketing carrier on a US originating/terminating ticket chooses to apply the IATA MSC rule). DL glosses it over as "generally the first international operating carrier" whereas NZ gives a more detailed explanation. It's the same rule and same term and DL is using those same rules when they apply the IATA rule.