Seems that the old one "Divide them to conquer separately" always works.

Its because often unity is worse than division.

Unity allows easy spreading of disease and corruption, cancer cannot spread between different people. If a union in one country is corrupt, it won't automatically affect the unions in another country.

China was a united entity against the mongol invasion, didn't work out very well, because you take out the center, the rest collapses.

Europe was deeply divided, and just because your neighbouring castle surrendered, doesn't mean you will. Because you are the local noble who owns the land, rather than some bureaucrat employed by a distant emperor.

> China was a united entity against the mongol invasion, didn't work out very well, because you take out the center, the rest collapses

I am sorry, is this like troll logic?

The entire history of war is large and powerfull empires bullying smaller ones.

This is so silly I am not even sure how you can argue this. Like did USA fight world war 2 as 50 seperate armies, one for every state?

I'm not sure what 'entire history of war' you are reading. Did you only read 19th century history or something? If large empires always had an advantage, then you would see endless snowballing, and only end up with mega-empire-blobs, and one-world-government.

That is not the case. You have period of imperial blobbing, and also period of intense fracturing. Europe fractured after Rome, because smaller polities were much easier to maintain, with fewer layers of bureaucracy to feed. The small Frank kingdom (that only owned half of France) was able to fend off the great Jihad from the Umayyads that had crushed the Visigothic Spain. Whereas if you took out Rome, or the Chang-An of China, the rest of the empire would be paralyzed and unable to act.

I don't know what re-unionizing in the face of a corrupt union entails, but presumably if you can pay people's salary while they strike you're at least part of the way there?

Even casting off the yoke of a union that no longer represents you is hard in the US:

https://freebeacon.com/policy/labor-leaders-say-illinois-fir...

https://www.nhregister.com/news/article/New-Haven-firefighte...

https://www.shrm.org/resourcesandtools/legal-and-compliance/...

I don't think I'd care to imagine fighting a corrupt union entails.

Mexico has both employer-controlled sham unions and real unions. While there is certainly tension between US and Mexican workers you overstate the situation.

US unions would like Mexico to have strong unions both out of sympathy and self-interest. The more protections Mexican workers have the less attractive it is to move jobs from the US to Mexico.

US unions successfully fought to include pro-union provisions in the USMCA (Trump's NAFTA "renegotiation"). They're using those provisions to help Mexican workers form real unions and defeat the sham employer unions. We don't yet have much experience with how these provisions will work out, but there have been limited early successes.

See for ex https://apnews.com/article/biden-labor-unions-united-states-...

I was thinking more of this: https://jacobin.com/2016/08/mexico-teacher-union-strikes-oax...

Describing the prosecution of the head of the teachers union in 2013:

> Mexican Attorney General Jesús Murillo Karam charged Gordillo with money laundering, saying she had used the union funds to pay for airplanes, pilot training, her plastic surgeries, and purchases of luxury items in the United States. Juan Díaz de la Torre, who was a loyal member of her union caucus, became head of the union.

> While Gordillo was very likely guilty of the embezzlement of which she was accused, such practices are common in the Mexican labor bureaucracy. The motive for jailing her was political: first she had betrayed the PRI, and then she had opposed Peña Nieto.

The part about “such practices are common in the labor bureaucracy” is telling.

Corruption is so common, that any prosecution can (accurately!) be labeled political is one of the best signs of a corrupt system.

This isn’t about an employer controlled union. The union is heavily autonomous.

But if Mexican leaders wanted to get rid of unions, all they would have to do is enforce the law.

Guiliani did something similar when mayor of NY. He announced sweeping investigations into union corruption, then negotiated very favorable contracts while prosecution was hanging over union leaders heads, then called off the investigations when he got the terms he wanted.

Maybe I was wrong to focus on employer controlled vs real unions. That's certainly a problem, but as you point out it's not the only problem.

Here's the broader point I was trying to make: Mexico has a problem with corrupt unions. But US unions are trying to help Mexicans solve that problem, not abandoning cooperation with anyone in the country.

I'm not sure if the US teachers union specifically is involved. They'd have less incentive to be because you can't replace a US teacher with a Mexican one.