Cooperate with whom? Presumably struggles by non-Americans in other lands? Clearly they can, as the Spanish Civil War and other struggles attest. Should they? That is the more difficult question. Oppressed peoples often accept offers of "help" from outsiders, whatever "help" might be construed to mean. Whether one should offer assistance is another question entirely. Different struggles have very different and specific determining characteristics. One should be well-informed about what is going on in order to be a help rather than a hindrance. Coming from the heart of the global capitalist machine, Americans are often bad at understanding where oppressed peoples in other parts of the world are coming from. One would need to talk with a lot of the people involved and hear differing views and opinions before being able to come up with a reasonably well-informed perspective.