Lincoln made it very clear while he was running for the office of President that he did not want to disrupt slavery where it existed. His top priority was saving the union, and that meant waiting as long as possible to declare emancipation.
The best scenario for the process of cultural diffusion is the following:
<span> a merchant traveling to sell his goods in another society
</span>
the first two options are not even relating to culture, and while the third one is, it is not a cultural diffussion, but a development that could have happened in one culture only.
What quotation? You didn’t put it in.