They are a great idea but....
1. Most are pro-capitalist, bureaucratic, not revolutionary and, therefore, generally promote the Dem party at the expense of one on one organizing, and accept sell-out contracts during bargaining so that they can continue getting their 6-fig salaries. This is bad.
2. unions in the U.S. are no longer "mandatory." The closed shop union is a thing of the past, thanks to a corporate-sponsored SCOTUS ruling. So, no one is ever "forced" to be in a union anymore.
3. there are some revolutionary unions in the U.S., like the IWW, whose ultimate goal is overthrowing capitalism; whose leadership serve as "delegates" who are recallable by the membership at any time; who are anti-imperialist; who are in solidarity with ALL workers, in ALL countries, of all skills and backgrounds; but who still fight for day to day reforms like healthcare, benefits and higher pay
4. Even though the majority of unions are pro-capital and pro-Dem, they still help keep wages from falling further than they have and help prevent workers from losing any more benefits than they have. However, because the capitalists have successfully decimated the labor movement, they are having a much smaller affect in this respect. Hence, the correlation between growing CEO pay vs worker pay and declining union membership
