Regarding your question about trade unions: The Guardian considers that this is a matter for each National Spiritual Assembly to advise the believers on. As long as the trade unions are not members of any particular political party, there does not seem to be any objection to the Bahá’ís belonging to them.
The British National Spiritual Assembly wrote to the Guardian as follows:
"In this country the law recognises strikes as legal when called by properly constituted authorities such as a Trade Union, and our own understanding is that in such circumstances the Bahá’í teaching, in spite of ?bdu’l-Bahá’s express disapproval of strikes, neither requires nor forbids an individual to strike but leaves him free to decide for himself in the particular circumstances of his case what is the proper course of action.”
The Guardian’s secretary replied on his behalf in a letter dated July 11, 1956:
"As regard strikes, the Guardian feels that your own understanding of the matter as expressed in your letter is quite correct, and he does not see the necessity of adding anything to it. We should avoid becoming rigid and laying down any more rules and regulations of conduct.”
Based on the above guidelines, we are to emphasize the following points.
1.A Bahá’í can become a member of a trade union as long as he is not required to also join a political party.
2.?bdu’l-Bahá in general disapproved of strikes. The Bahá’í attitude is that when the law recognizes strikes as legal, as when called by a properly constituted authority such as a trade union, the Bahá’í teaching neither requires nor forbids an individual to participate in the strike but leaves him free to decide for himself what is the proper course of action in the particular circumstances.
(Universal House of Justice, Lights of Guidance, no. 2121)