In the aftermath of "Samaritan Snare", we have to accept that "joining" the UFP does not refer exclusively to becoming a member. Wesley would need to be interpreted as having spoken of "joining the cause" or forming an alliance. In contrast, Daniels is very explicitly speaking of "the Federation", and stating that the listed cultures are "unified"; it takes more work to interpret this as referring to a loose alliance wherein the listed cultures merely boost the separate UFP with their presence.
"Samaritan Snare" is interesting for all the reasons the writers never intended. Why does Wesley start babbling about Klingons when Picard mentions Starbase Earhart? And why does Picard's face light up when Wesley does so?
Because Klingons and Earhart are somehow related, and Picard appreciates that Wesley knows of this history, and of history in general?
Or merely because the alliance with Klingons is a watershed Wesley knows is temporally proximal to Picard's Academy years, and Picard doubly appreciates Wesley knowing his history and Picard's?
Generally, if I were to talk to my son about my first car and he asked "Was this before the war, Dad?", my face would not light up...
Timo Saloniemi