But the unions use the money for a great deal more, including funding political activity directly and indirectly. And those forced to pay agency fees have nothing to say about how their money is spent. In 1988, the Supreme Court ruled that employees could ask for a refund of that portion of their fees that went toward politics and other activities unrelated to collective bargaining, but the decision has been widely ignored by the unions and is difficult to enforce. As a result, unions have huge treasuries to spend as they choose, with virtually no system of checks and balances. But the problem goes beyond coercion in the way in which the money is collected.
Many unions spend the money illegally, too, but their activities are difficult to detect.
Unions are allowed to spend money communicating with their members on issues or publicizing their endorsements of candidates. They may also register union members and their families and get out the union vote on Election Day. They can also assign union staff to political campaigns, so long as the cost doesn't exceed campaign contribution limits. I saw some of these abuses when I was an official for the American Federation of Teachers from 1974 to 1983. If anything, the problem has gotten much worse in the last 20 years.