GUWonder

For a US citizen without a SSA number, even if their US passport application is rejected, it may still be possible to get a SSA number once in the US. I'm not sure if it is still the case or not, but before it was possible to get a SSA number even for US citizens outside of the US without a current US passport -- not always a walk in the park, and not without some resistance often enough, but it was done.

[While it may be absurd that an expired US passport is not always ordinarily accepted as evidence of identity, it's no more bizarre than some European governments accepting valid foreign (e.g., US) passports for entry and for proof of identity in some cases but then refusing to accept the valid US passports as proof of identity for other purposes. For example, the Swedish government rather routinely refuses to accept non-EU/EEA passports as evidence of identity of the foreign citizen parent(s) named on Swedish birth certificates but they will accept the non-EU/EEA passports as evidence of identity for other purposes. [To see an example of this nonsense courtesy of governmental bureaucracy, check out the Stockholm police station where Swedish passports applications are accepted in person. Then try to see how minor Swedish citizens with foreign parent(s) may involve the parent(s) asking some person -- random or otherwise -- to sign a document attesting to the identity of the foreign parent(s).]