And the last thing one wants to be is weak in the eyes of any potential adversary.
Someone posted the other day a comment by I think was from Dobrynin when he was Russian foreign minister. The comment was to a question posed in 80 about what would have happened to Iran if they had done to it what Komani et al did to the US embassay and staff in 79. He answered: it is now 11 am. At 1 PM there would be no Teheran. Message sent, message received, no problem for the USSR during those times.
Were Reagan president today, he would quietly tell those jokers over there, one thing happens here, you are history.