You have some facts wrong. At the time of the 1980 manifesto, the Church reached an amnesty deal with the government saying that it would cease plural marriages.
I am not sure my facts are wrong. Was the manifesto really given with and intent to end plural marriage? Was the entire FP and Q of 12 behind it? If I recall President Woodruff had it published when I believe 8 members of the 12 were out of town. Once public they were sort of stuck with it. But I recall an apologetic on polygamy on the FAIR web site that, when explaining post manifesto polygamy, the author argued that the manifesto was written to appease the federal government but it by no means was entirely binding on the Church. I can dig this up if you would like.
Pres. Smith acknowledged the deal explicitly in Senate testimony. Pres. Smith also acknowledged that Pres. Woodruff ordered an end to plural marriage in the U.S., and that Pres. Woodruff stopped living with his plural wives. But, Pres. Smith also acknowledged that other general authorities were slow to comply, including himself Pres. Smith did not take on new wives but continued to cohabit with old wives.
Can you tell me if President Woodruff followed this immediatly upon issuance of the manifesto or if this came later?
So, it wasn't really a matter of being "carefully worded" when you view it in context with the deal reached with the Justice Department. No new plural marriages. None.
Are you proposing there were no sanctioned plural marriages after 1890? I do not think that is correct. Before I spend time finding evidence for this could you clarify the comment above please?