Can this not be proven from the Talmud in tractate Yevamot (at any rate in the case of violating a prohibition)?
"There is no duress regarding forbidden sexual relations, because there is no erection except willingly."
So what of it? He became aroused willingly and had intercourse under duress.
Rather, must we not say that someone who knowingly puts himself into a situation in which he will transgress under duress is considered to have acted willingly?

There are quite a number of sources in the Talmud that apparently contradict one another on this point (and in particular one should compare it to the rule of something whose beginning was in negligence). Specifically regarding erection, we are dealing with pleasure, and perhaps there one can invoke the reasoning of "since he derived pleasure," which creates liability even if he put himself into a situation of duress.

I have a few questions about this, if possible:

In the answer above it says that one who puts himself into a situation of duress, if he did not do so intentionally in order to evade the commandment, but rather wanted the coercive situation for its own sake, is considered under duress (and as I understand it: therefore it is permitted to put oneself into a coercive situation if one has a direct interest in it). The reasoning seems novel to me.

A. Is the background to this reasoning from the Talmudic topic of when there is no other path?

B. In a lecture by Rabbi Zalman Nechemia Goldberg, linked above, a distinction is made between preparation and getting caught up in a situation. If one did not prepare the four species, he is not under duress on Sukkot. If one set sail on a ship before the Sabbath, he is under duress on the Sabbath itself (and the rabbis decreed a restriction for the three days before). I understand that the lenient logic of having a direct interest applies only to getting caught up in a situation, not to preparation. Meaning: even according to your view, that someone who puts himself into duress because of a direct interest in the inducing situation is considered under duress, you would still say that even if he has a direct interest in watching a movie instead of going out to the market to buy the four species, he is not under duress when the holiday of Sukkot arrives. Could you explain the actual distinction between preparation and getting caught up in a situation?

C. In that lecture it is explained that putting oneself into duress is forbidden, whereas putting oneself into a situation of danger to life is permitted. [And if the obligation has already taken effect, then even putting oneself into a situation of danger to life is forbidden. According to the view of the author of Ba'al HaMaor, one does not circumcise an infant on the Sabbath if one will afterward need to heat water.] For example, surgery on the eve of Yom Kippur is permitted even though it is known that it will lead to prohibited labor on Yom Kippur, because of danger to life. And it sounds as though if it would lead to labor because of duress, it would be forbidden (for example: if the king said that whoever performs surgery and does not do labor the next day will be put to death). And this is so even though he has a direct interest in the surgery and is not doing it in order to evade the commandment. So is your opinion here different from Rabbi Zalman Nechemia Goldberg’s?
What is the boundary here? After all, the implication is that all the problems with putting oneself into duress apply only to a cunning evildoer whose sole purpose is to avoid the commandment.

D. What happens in the case of a commandment that is contingent on an act or a condition (and not merely lacking the proper time, like the four species)? For example, if someone knows that the king will prevent him from reciting Grace after Meals, is he allowed to eat bread anyway (which he likes)? [I can’t quite define the different sides clearly to myself, but I have a feeling there may be a difference.]

A. It seems like simple reasoning to me. And indeed it appears there as well.
B. I no longer remember what exactly is being discussed. But from your description the distinction seems straightforward. What is unclear about it? The distinction is self-evident. Of course, there may be gray cases, and each one would need to be considered on its own.
C. I don’t know. I’d have to see the proofs and the cases.
D. As I recall, there is a responsum of the Rivash about this (where a community placed someone under ban not to come to the city so as not to play, and someone brought himself into the city).
This topic was discussed here three years ago, so if you want to raise an issue for discussion, it’s better to define it well and bring the relevant information, and then discuss it.

Thank you.
(I thought I had defined it well, to the best of my ability, and brought the relevant information. Accepted.)