So Unions destroy Wealth...

At least according to a working paper by David Lee and Alexandre Mas (Freakonomics):

a policy-induced doubling of unionization would lead to a 4.3 percent decrease in the equity value of all firms at risk of unionization.

Walmart is, of course, famous for shutting down any store that has a successful unionization vote - which, as Freakonomics Blog notes, seems to support this aggressive approach. It also calls into question the wisdom of the "Employee Free Choice Act". While I should first state that I think unions used to have a role, I question why government policy now effectively allows the creation of a monopoly on labor. Another question: given that there are so many pensions run by unions, would they therefore have a fiduciary duty not to invest in firms where unions play a significant role?