Tithes! They are an offering where you give ten percent to the church.
The level of immigration between 1930 and 1945 is most directly related to the Great Depression and World War ll. Due to the poor economy with little opportunity for better living standards, very few people were willing to immigrate to the USA.
Are you looking for just one word? How about "unite"? Labour unions were organizations of workers. So any similar word could fit: organize themselves, come together etc.. Also, they were fighting for better rights for workers.