In principle, every American citizen has an equal say in our political process. In practice, of course, some of us are more equal than others. Billionaires can field armies of lobbyists; they can finance think tanks that put the desired spin on policy issues; they can funnel cash to politicians with sympathetic views (as the Koch brothers did in the case of Mr. Walker). On paper, we’re a one-person-one-vote nation; in reality, we’re more than a bit of an oligarchy, in which a handful of wealthy people dominate.

Given this reality, it’s important to have institutions that can act as counterweights to the power of big money. And unions are among the most important of these institutions.

You don’t have to love unions, you don’t have to believe that their policy positions are always right, to recognize that they’re among the few influential players in our political system representing the interests of middle- and working-class Americans, as opposed to the wealthy. Indeed, if America has become more oligarchic and less democratic over the last 30 years — which it has — that’s to an important extent due to the decline of private-sector unions.

And now Mr. Walker and his backers are trying to get rid of public-sector unions, too.

There’s a bitter irony here. The fiscal crisis in Wisconsin, as in other states, was largely caused by the increasing power of America’s oligarchy. After all, it was superwealthy players, not the general public, who pushed for financial deregulation and thereby set the stage for the economic crisis of 2008-9, a crisis whose aftermath is the main reason for the current budget crunch. And now the political right is trying to exploit that very crisis, using it to remove one of the few remaining checks on oligarchic influence.

So will the attack on unions succeed? I don’t know. But anyone who cares about retaining government of the people by the people should hope that it doesn’t.

This is exactly right. No, unions aren't always perfect. So what? They're all that's left to protect the rest of us. Remember: The enemy of my enemy is my friend.