What did Pol Pot expect to gain from his raid against Ba Chuc Vietnam in April 1978?

Question

This was a major raid by Khmer Rouge forces over the Vietnamese border, resulting in the deaths of over 3000 Vietnamese.

For more information and details, please see:

https://en.wikipedia.org/wiki/Ba_Chúc_massacre

https://youtu.be/Ei9W8hW29GQ

Was Pol Pot that foolish enough to think that he could carry out such a raid without a severe response from Vietnam? It turned out that this raid was a major catalyst leading to Vietnam’s invasion of Cambodia and subsequent overthrow of the Khmer Rouge.

The only logical explanation for this raid that I can think of is that Pol Pot was using Vietnamese border raids as a way of distracting the militant energy of his subordinates instead of letting this militancy result in a potential coup against himself. If this was the case, this got out of hand quickly. Or this was a decision made by a local Khemer Rouge commander that Pol Pot was not aware of.

In any case, this raid would later set a lot in motion two invasions (Vietnam vs Cambodia and China vs Vietnam) and years of insurgency in Cambodia.

Answer 1

This was not an isolated incident, but rather a part (see, e.g., Thổ Chu Islands) of a "creeping aggression".

Consider

1. Khemer Rouge were allies of China
2. Vietnam was allied with USSR
3. USSR & China were unfriendly
4. Cambodia & Vietnam were neighbors and, as is common among neighbors, traditionally hostile to each other and had territorial issues.

The only real question is not why but why now. This is explained by the general cooling off of the relationships between China and Vietnam, following the end of the Vietnam war.