Rafah: Was Biden's red line crossed? By most measures, yes. By Biden's measure - probably not
Just over two weeks ago, President Biden drew a clear red line for his "old friend Bibi".
He told Israeli Prime Minister Netanyahu not to go into Rafah.
"If they go into Rafah, I'm not supplying the weapons... to deal with that problem," he told CNN.
It was widely interpreted as the moment the American president was no longer going to be taken for a ride by Netanyahu.
But then Netanyahu's soldiers entered Rafah. They avoided the city centre though, thus allowing Biden the wiggle room to say his line hadn't been crossed.
Israeli forces instead took over the border crossing on the edge of the city, cutting off a key transit point to Egypt and with it, the ability to get aid in and injured people out.
Since then, Israeli military operations have continued daily but did not, the White House said, constitute "going into Rafah".
Pushed on what appeared to be an increasingly elastic red line, Biden's national security adviser, Jake Sullivan, told us last week that there was "no mathematical formula" for working out when it had been crossed.
"What we're going to be looking at is whether there is a lot of death and destruction from this operation or if it is more precise and proportional," Sullivan said from the White House podium.
Then, on Sunday night, dozens of Palestinians were not just killed but burnt alive, decapitated, maimed in an attack on a displaced people's camp on the edge of Rafah.
Bushra Khalidi from Oxfam said of the scene: "There are no more words... we saw images of children blown to pieces, burnt to crisp, and I'm sorry to be graphic but that is what we saw."
Gaza's civilian casualties are either a "mistake", or "a consequence of war", or "Hamas's fault".
Often the civilian killings are seen by Netanyahu's government and its supporters to be the proportional or acceptable cost of taking out Hamas commanders.
The justification is frequently packaged up as self-defence - despite stiff criticism from international bodies and eminent legal authorities.
This time, in Rafah, Prime Minister Netanyahu said that two Hamas commanders accused of carrying out attacks in the West Bank were killed, but "a technical failure" led to 40+ civilians being killed.
Remember Jake Sullivan's parameters set out last week? "Precise and proportional... a lot of death and destruction."
Unquestionably there was horrific death and destruction on Sunday night. It seems mad even to have to point this fact out.
"Precise and proportional"? Well, it will take some considerable verbal acrobatics for President Biden to conclude that what happened in Rafah was either proportional or precise.
So watch the American president over the next 24 hours.
I suspect he will say that his red line has not been crossed. He will indicate that the strike, devastating though it was, did not constitute a red-line-crossing ground force smashing into Rafah.
Why? Because he would have to follow through on his threat to cut off military aid.
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And if he did that, he would face an overwhelming chorus of opposition among politicians on Capitol Hill and key donors just months before the US election.
Congress incidentally is poised to invite Netanyahu to address a joint session.
As he has so many times before, President Biden thought his "old friend Bibi" would listen to him.
But the idea that Netanyahu is listening to anything President Biden is saying is stretching credibility to its limit.