Cambridge, Mass.

A CENTRAL principle of American political life is that everyone gets to choose which candidates to support. The idea that the government could force us to support those we oppose is anathema. But this unacceptable state of affairs is one of the unintended consequences of the Supreme Court’s decision in the 2010 Citizens United case.

That’s because the vast majority of people who work in the public sector — state, local and federal employees — are required to make contributions to a pension plan. Nearly all states make participation in a pension plan mandatory and a “condition of employment” for public employees. To get and keep your job with the government, you have to give some of your paycheck to the pension plan.

Public pensions, moreover, are so-called defined benefit plans, which means that employees don’t have a say in how their mandatory contributions are invested. The employees cannot request, for example, that their money be used only to buy government bonds or that it be invested only in certain mutual funds or only in select corporations.

Instead, the employees’ money is invested according to whatever decisions the pension plan’s trustee makes. And, not surprisingly, pension plans invest heavily in corporate securities: in 2008, public pensions held about $1.15 trillion in corporate stock.