He might if he wants their options not to vest. [Edit: Or to have to pay their golden parachute.]

I wonder if even Musk would be so publicly ruthless as that?

I wonder how many his employees in Tesla/SpaceX/where ever are currently incentivised by stock options, who’d watch their boss doing that to Twitter people and wonder why they bother working evenings and weekends, if the options can be yanked as cruelly as that?

Musk made an offer, voluntarily closed off his ability to back out, then tried to back out and couldn't. He has been thoroughly outmaneuvered by Twitter's management (or outmaneuvered himself, same effect). So I'm not super high on his ability to foresee consequences at the moment.

Also, because of being outmaneuvered, he may be seeking any chance to stick his finger in the eye of the people who did it. That the logical consequences will be that his finger gets cut off... well, as I said, I'm not sold on his foresight at the moment.

I think it was a good gamble. If old management had budged by even 1% or 2% of the original deal, the savings would have easily paid for all the lawyers Musk and Twitter had to hire. Just a calculated risk that didn’t pay off. That’s how calculated risks go sometimes.

there's legislation around layoffs you can't handwave with "at will"

For the downvoters - google the WARN act

WARN Act just means you have to give people notice. You can revoke their credentials and tell them to stay home while the 60-day clock runs. You just have to keep paying them for that time.

And presumably their stock also vests?

The WARN act only means you need to give 60 days notice in certain types of mass layoffs. Given that Twitter hasnt done any mass layoffs yet, speculating on whether or not they gave enough notice under the act is a bit premature.

Twitter hasn't, but it seems that there is some internal tension around it. Making working conditions worse to force people to quit, setting impossible deadlines to fire en masse "with cause," and just generally shedding employees but not calling it a layoff all seem to be in play.

Elon is interacting and trying to dodge this act. He seems to want to cut Twitter's workforce at a scale that the WARN act covers.

Every jurisdiction is different in details, of course, but "at-will" just means you can fire someone, not that you get to decide what happens after unilaterally (e.g. you may owe severance)

Is that the case in CA or NY? I don't know where else Twitter has large offices, but presumably these would be two of the largest. I'm pretty sure in CA the employer doesn't automatically owe severance. It's usually offered in return for a promise not to sue (and sometimes also a promise not to speak ill of).

There's the WARN Act, but I don't think that impacts what happens after a duly-warned layoff, unless I'm mistaken?

The California WARN Act requires companies of a certain size who are laying off 50+ employees to give 60 days notice to the employees.

Technically the company can't get around the WARN act through severance but it is essentially pre-paying the damages so there's no reason to go to court.