I am not certain which lecture you are referencing. I don’t remember using those exact words. Are you talking about Southern interest in purchasing federal property in 1860 and 1861?
If so, the Southern States, mainly South Carolina but there were discussions in other States as well, sent commissioners to Washington D.C. to purchase federal property and settle any outstanding debt issues. They were rebuffed by the Lincoln administration. Secretary of State Seward feigned sick so he did not have to meet with them. If the Union had negotiated with South Carolina, that would be both a de facto and de jure recognition of secession, something Lincoln refused to accept.