“Raise our taxes!” Can you imagine chanting such a slogan at a public rally? Neither could most Americans.

There is one notable exception, however: government-union activists. They’re pretty explicit these days about their desire to see taxes go up.

If that surprises you, you may be unaware of how dramatically the face of organized labor has changed over the last few decades. There’s a very good reason they’ve got your wallet in their sights – more and more, that’s where their wages comes from.

To see why, it’s vital to understand the difference between unions in the private sector (steelworkers, autoworkers, etc.) and unions in the public sector (government).

Private-sector union membership has been in steep decline. Back in 1980, one out of every five private-sector workers belonged to a union. Thirty years later, less than 7 percent do. That’s fewer than one in 14. But over the same period, government-union membership has been climbing. Today, in fact, more than half of all union members (52 percent) work for the government.

So when they lobby “management” (i.e., elected officials) for wage hikes and other benefits, that money isn’t coming out of the bank account of some private company. It’s coming from you and me. When those elected officials say, “We’re in the red. We have to balance our budget, and we can’t pay you more,” government-union activists reply: “Raise our taxes!”

Of course, they don’t just say it. Government-union leaders spend millions of dollars trying to elect politicians who are open to tax hikes. They were the top outside spenders in the last election. They put their money where their mouth is, all in the hopes of putting your money where their coffers are.

This circular arrangement may be nice and cozy for union leaders and their big-government buddies, but it’s a disaster for the taxpayers they’re exploiting. If taxes aren’t raised to satisfy their demands, will workers “strike” from providing government services? They can – and they have (e.g., the New York City transit strike of 2005). Even President Franklin D. Roosevelt, who signed the National Labor Relations Act, called such a prospect “unthinkable and intolerable.”

As George Meany, president of the AFL-CIO from 1955 to 1979, once noted, “It is impossible to bargain collectively with government.” President Roosevelt agreed: “The process of collective bargaining, as usually understood, cannot be transplanted into the public service.” When it is, it sets up a chain reaction of painful choices.

That’s why matters in Wisconsin came to a head. In an effort to balance his state’s budget, Gov. Scott Walker proposed a plan that said 1) workers would no longer be forced to pay union dues, 2) voters would have to approve any wage increases that exceed inflation, and 3) public employees had to contribute more toward their health care and pension plans.

No wonder it passed the legislature; these are hardly radical changes. Workers can still negotiate wages – voters just have the final say. Dues are no longer compulsory, but workers can continue to pay them. (And if what the unions do is so valuable, they should have nothing to worry about, right?) Millions of private-sector workers contribute to their own pensions and health care plans. Why should public-sector workers be any different?

But anyone who listened to the hysterical protesters in Wisconsin saw people operating on an entirely different plane of reality. To hear them tell it, Walker is the reincarnation of Adolf Hitler, and powerful government unions are not a public policy choice but a human right. “It is shameful to play politics with American workers and their families,” Rep. Elijah Cummings, D-Md., told Gov. Walker when he testified before Congress.

What irony. There’s a group playing politics with American workers and their families, all right. They’re the ones demanding that you and I cough up still more money to fatten their paychecks – or else. Talk about “intolerable.”