With all due respect that clause was not being infringed. There were fugitive slave laws on the books, and a large number of laws in place to enforce it.
Four months after he said slavery should be abolished, he admitted their was a Constitutional right to own slaves as well as having escaped slaves returned.
In both speeches Lincoln was acknowledging the legality of slavery, but he wasn't supporting it and he did expect that the people of the United States would choose to end it.
Please read Madison's report on the Alien and Sedition Act already posted.
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and later upheld by the Supreme Court
"When plunder becomes a way of life for a group of men living together in society, they create for themselves in the course of time, a legal system that authorizes it and a moral code that glorifies it."
Frederick Bastiat, 1850
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Why should the Constitution only protect the leaving party and not the party staying?
Because the party staying is the one that breached the compact. Once that compact was breached, it was null and void by law. The 'terms' no longer existed for the leaving party.
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We've had this discussion before, NS. Each time, you live up to your screen name by trying to argue assertions that were never made, breeze right over points made by the other party (no matter how well-sourced they are) and rarely offer any sources of your own.
Good evening.