Complex sentence: Some argue this definitively turned the TIAR into a dead letter, including the Mexican government, which withdrew from the treaty in 2001 citing the Falklands example, though notably Argentina itself is still a TIAR member.
Split into simpler sentences: Some argue this definitively turned the TIAR into a dead letter. Furthermore, Mexico withdrew from the treaty in 2001 citing the Falklands example, though notably Argentina itself is still a TIAR member.