In 1968, the Canadian bishops issued a response to Pope Paul VI's encyclical on contraception "Humanae Vitae." While veiled in pseudo-sacral language, the statement is a clear rejection of the Church's teachings.
Paragraph 26 is key. The statement bases itself on the dubious premise that Canadian Catholics are so weak that many of them simply cannot help having contraceptive intercourse: "It is a fact that a certain number of Catholics, although admittedly subject to the teaching of the encyclical, find it either extremely difficult or even impossible to make their own all elements of this doctrine."
It then leaps from there to the all-too-familiar appeal to conscience:
In accord with the accepted principles of moral theology, if these persons have tried sincerely but without success to pursue a line of conduct in keeping with the given directives, they may be safely assured that whoever honestly chooses that course which seems right to him does so in good conscience.
The document fails to teach that this is true if and only if the conscience is well formed — and a well-formed conscience may never choose to use contraception to prevent birth.
The Winnipeg statement also attempts to divorce moral teaching from dogma: "Since they are not denying any point of divine and Catholic faith nor rejecting the teaching authority of the Church, these Catholics should not be considered, or consider themselves, shut off from the body of the faithful."
And later: "The unity of the Church does not consist in a bland conformity in all ideas, but rather in a union of faith and heart, in submission to God's will and a humble but honest and ongoing search for the truth."
Armed with the idea that "bland" conformity to magisterial teaching was unnecessary, the Canadian Church was primed for a moral and spiritual collapse.
The Winnipeg Statement was excitedly embraced by the Left while at the same time blasted by orthodox Catholics. Despite immediate pressure to revoke the Winnipeg Statement, the Canadian bishops doubled down a year later and issued another statement declaring that they stood behind what was said in Winnipeg.
A 2008 pastoral letter titled "Liberating Potential" is seen by many as an apology for the Winnipeg Statement — but it remains the case that the Canadian bishops as a body have never officially retracted Winnipeg.