Doesn't really prevent a strike though: it just makes it cost more. Here in Massachusetts it's illegal for public school teachers to strike, yet it has happened a couple times in the last year. In one case the teacher's union was fined: https://www.bostonherald.com/2023/02/08/woburn-teachers-turn...
The most recent attempt at a railroad strike was stopped by Congress imposing management's contract. But that's not a general prohibition against striking.
I tend to think UPS is a lot more like pilots than railroad workers, especially since there are alternatives if you really do need to ship something right away.
Why can't they just tell that they will nationalize them if they don't agree to demands. If they don't and allow strike to happen. Just take over the private ownership resetting both equity and bond holders and give the gains to workers...
Do you think the Democratic or Republican candidate gets the nomination and wins the presidency because they do what the people want? They get that nomination and win the presidency because they convince a small constellation of large companies to buy election advertising on their behalf in order to influence the outcome of the election for the candidate that each company in that constellation feels would serve their interests best.
So of course the House of Reps, Senate, and President are all going to support the biggest corporations - they don't want to spend their own money campaigning and they don't want to go back to a life where they don't have influence and aren't wined and dined for things.