J1 NRA和citizen联合报税

citizen和J1 NRA共同报税。J1 NRA还能继续享受tax treaty？
以下是我找到的不完整信息：
https://www.irs.gov/individuals/...sident-alien-spouse
Generally, neither you nor your spouse can claim tax treaty benefits as a resident of a foreign country for a tax year for which the choice is in effect. However, the exception to the saving clause of a tax treaty might allow a tax treaty benefit on certain specified income.  
不过后半句也写了： However, the exception to the saving clause of a tax treaty ...
中美1984协议是有 saving clause 的，位于同一天签署的Protocol (补充条款) 1 的第2段，指出美国对其公民可征税；以及对其resident（也就是税法上的联邦RA）征税时，依然排除条约正文包括19, 20(b), 20(c) 在内的多条Article的情况？