Writing for the latest Forbes magazine, Steve Forbes offers the following assessment of a United Nations scheme to levy a 1 percent wealth tax on everyone with a net worth exceeding $1 billion.

Such an “intriguing” idea would raise revenues to help the world’s poor. Baloney. Such an exaction would damage the world’s economy, which would mean less upward-mobility opportunity for those who have the least.

The UN and organizations of its ilk still have a cartoonish conception of what wealth actually is. Most wealth these days doesn’t consist of piles of cash and gold. Global billionaires are not like Scrooge McDuck, sitting in their money bins and counting coins. The bulk of this wealth can be rather ephemeral, simply an evaluation of assets, whose worth changes constantly. Mark Zuckerberg’s Facebook shares are currently worth about $20 billion, which means he’d be liable for $200 million to the UN. But that evaluation assumes Zuckerberg and capable executives will continue to run the company. What do you think the shares would be worth if the Postal Service took over the company? And what if Facebook fails to generate expected future revenues and profits? Its market value will plummet. Look at Yahoo’s market value today compared with what it was three years ago—or Groupon’s or Zynga’s a few months back.

Class warriors assume wealth is just meant for consumption. But the reality is that virtually all of it is invested and reinvested. Take it away from those who create and/or know how to manage it and it goes the way of water in the desert.