Earlier quoted context omitted.
The default for the US is "at-will employment", which means that your employer can fire you at any time, no reason needed. The definition of "just cause" would be collectively bargained, so both management and the union will understand and agree on what constitutes just cause or not. FWIW, layoffs are regulated differently from firings.
>The default for the US is "at-will employment", which means that your employer can fire you at any time, no reason needed. That seems... fine? In most transaction neither party needs to give "just cause" to terminate a contract. Imagine having to give documentation to move out of your current apartment, for instance. Getting fired is disruptive to someone's finances that some notice/severance would be justified, but…
In other words, one side will win, or both will compromise. It's just another contract negotiation, like any other between two parties. Unions are allowed to do it with businesses, just like businesses are allowed to do it among themselves. This is literally the ruling ideology of the West and has been for generations, but somehow when a union takes advantage of it, that's radical marxism.