Allister Heath, the superb economic writer from London, recently warned that governments are undermining incentives to save.

And not just because of high tax rates and double taxation of savings. Allister says people are worried about outright confiscation resulting from possible wealth taxation.

It is clear that individuals, when at all possible, need to accumulate more financial assets. ...Tragically, it won’t happen. A lack of trust in the system is one important explanation. People simply don’t believe the government – and politicians of all parties – when it comes to long-terms savings and pensions. They worry, with good reason, that the rules will keep changing; they are afraid that savers are an easy target and that they will eventually be hit by a wealth tax.

Are savers being paranoid? Is Allister being paranoid?

Well, even paranoid people have enemies, and this already has happened in countries such as Poland and Argentina. Moreover, it appears that plenty of politicians and bureaucrats elsewhere want this type of punitive levy.

Here are some passages from a Reuters report.

Germany's Bundesbank said on Monday that countries about to go bankrupt should draw on the private wealth of their citizens through a one-off capital levy before asking other states for help.

Since data from the IMF, OECD, and BIS show that almost every industrialized nation will face a fiscal crisis in the next decade or two, people with assets understandably are concerned that their necks will be on the chopping block when politicians are scavenging for more cash to prop up failed welfare states.

Though to be fair, the Bundesbank may simply be sending a signal that German taxpayers don't want to pick up the tab for fiscal excess in nations such as France and Greece. And it also acknowledged such a tax would harm growth.

"(A capital levy) corresponds to the principle of national responsibility, according to which tax payers are responsible for their government's obligations before solidarity of other states is required," the Bundesbank said in its monthly report. ...the Bundesbank said it would not support an implementation of a recurrent wealth tax, saying it would harm growth.

Other German economists, however, openly advocate for wealth taxes on German taxpayers.

...governments should consider imposing one-off capital levies on the rich... In Germany, for example, two thirds of the national wealth belongs to the richest 10% of the adult population. ...a one-time capital levy of 10% on personal net wealth exceeding 250,000 euros per taxpayer (€500,000 for couples) could raise revenue of just over 9% of GDP. ...In the other Eurozone crisis countries, it would presumably be possible to generate considerable amounts of money in the same way.

The pro-tax crowd at the International Monetary Fund has a similarly favorable perspective, relying on absurdly unrealistic conditions to argue that a wealth tax wouldn't hurt growth. Here's some of what the IMF asserted in its Fiscal Monitor last October.

The sharp deterioration of the public finances in many countries has revived interest in a "capital levy"— a one-off tax on private wealth—as an exceptional measure to restore debt sustainability. The appeal is that such a tax, if it is implemented before avoidance is possible and there is a belief that it will never be repeated, does not distort behavior (and may be seen by some as fair).

The IMF even floats a trial balloon that governments could confiscate 10 percent of household assets.

The tax rates needed to bring down public debt to precrisis levels...are sizable: reducing debt ratios to end-2007 levels would require (for a sample of 15 euro area countries) a tax rate of about 10 percent on households with positive net wealth.

Many people condemned the IMF for seeming to endorse theft by government.

The IMF's Deputy Director of Fiscal Affairs then backpedaled a bit the following month. He did regurgitate the implausible notion that a wealth tax won't hurt the economy so long as it only happens once and it is a surprise.

To an economist, ...it's close to an ideal form of taxation, since there is nothing you can now do to reduce, avoid, or evade it—the holy grail of what economists call a non-distorting tax. ...Such a levy would entail a one-off charge on capital assets, the precise base being a matter for choice, but generally larger than cash left on kitchen tables. Added to the efficiency advantage of such a tax, many see an equity appeal in that such a charge would naturally fall most heavily on those with the most assets.

But he then felt obliged to point out some real-world concerns.

...governments have rarely implemented capital levies, and they have almost never succeeded. And there are very good reasons for that. ...to be non-distorting the tax must be both unanticipated and believed certain not to be repeated. These are both very hard things to achieve. Introducing and implementing any new tax takes time, and governments can rarely do it in entire secrecy (even leaving aside transparency issues). And that gives time for assets to be moved abroad, run down, or concealed. The risk of future levies can be even more damaging; they discourage the saving and investment that generate future capital assets.

Though these practical flaws and problems don't cause much hesitation on the left.

Here's what Joann Weiner recently wrote in the Washington Post about the work of Thomas Piketty, a French economist who apparently believes society will be better if higher taxes result in everyone being equally poor.

A much higher tax on upper income — say 80 percent — coupled with a significant tax on wealth — say 10 percent — would go a long way toward making America's income distribution more equitable than it is now. ...capital is the chief culprit... Piketty has another pretty radical, at least for the United States, way to shrink the share of wealth at the top — introduce a global tax on all capital. This means taxes on not just stocks and bonds, but also land, homes, machines, patents — you name it; if it's wealth or if it generates what tax authorities call "unearned income," then it should be taxed. One other thing. All countries have to adopt the tax to keep capital from fleeing to tax havens.

Writing in the New York Times back in January, Thomas Edsall also applauds proposals for a new wealth tax.

...worsening inequality is an inevitable outcome of free market capitalism. ...The only way to halt this process...is to impose a global progressive tax on wealth – global in order to prevent (among other things) the transfer of assets to countries without such levies. A global tax, in this scheme, would restrict the concentration of wealth and limit the income flowing to capital.

Not surprisingly, there's support in academia for confiscating other people's money. One professors thinks the "impossible dream" of theft by government could become reality.

...this article proposes a yearly graduated tax on the net wealth of all individuals in excess of $100 million. The rate would be 5% on the excess up to $500 million and then 10% thereafter. ...Such taxes are attacked as "class warfare" that runs counter to America's libertarian and capitalist traditions. However...the time may once again be ripe for adopting a new tax to combat the growing wealth inequality in the nation. ...wealth inequality harms the very social fabric of society. ...The purpose of the proposed Equality Tax would not be to raise general revenue, although revenue would be raised. Instead it would be focused on establishing a societal value that for the health of society, no individual should accrue wealth beyond a certain point. Essentially, once an individual has $100 million of assets, ...further wealth accumulation harms society while providing little economic benefit or incentive to the individual. ...At a minimum such a tax would raise at least $140 billion a year.

Let's close by looking at the real economic consequences of wealth taxation. Jan Schnellenbach of the Walter Eucken Intitut in Germany analyzed this question.

Are there sound economic reasons for the net wealth tax, as an instrument to tax stocks of physical and financial capital, to be levied in addition to taxes on capital incomes?

Before even addressing that issue, the author points out that policy actually has been moving in the right direction, presumably because of tax competition.

There has been a wave of OECD countries abolishing their personal net wealth taxes recently. Examples are Spain (abolished in 2008), Sweden (2007) as well as Finland, Iceland and Luxembourg (all 2006). Nevertheless, the net wealth tax repeatedly surfaces again in the public debate.

So what about the economics of a wealth tax? Schnellenbach makes the critical point that even a small levy on assets translates into a very punitive rate on actual returns.

...every tax on domestic wealth needs to be paid out of the returns on wealth, every net wealth tax with a given rate is trivially equivalent to a capital income tax with a substantially higher rate. ...even an - on aggregate - non-confiscatory wealth tax may at least temporarily actually have confiscatory effects on individuals in periods where they realize sufficiently low returns on their capital stock.

He then looks at the impact on incentives.

...a net wealth tax will have similar distortionary effects as a capital income tax. ...Introducing a comprehensive net wealth tax would then, through the creation of new incentives for tax avoidance and evasion, also diminish the base of the income tax. Scenarios with even a negative overall revenue effect would be conceivable. There is thus good reason to cast doubt on the popular belief that a net wealth tax combines little distortions and large amounts of revenue. ...A wealth tax aggravates the distortions and the incentives to evade that already exist due to a pre-existing capital income tax.

And he closes by emphasizing that this form of double taxation undermines property rights.

The intrusion into private property rights may be far more severe for a wealth tax compared to an income tax. ...It takes hold of a stock of wealth that consists of saved incomes which have already been subject to an income tax in the past... Our discussion has shown that economically, the wealth tax walks on thin ice.

In other words, a wealth tax is a very bad idea. And that's true whether it's a permanent levy or a one-time cash grab by politicians.

Some may wonder whether a wealth tax is a real threat. The answer depends on the time frame. Could such a levy happen in the next year or two in the United States?

The answer is no.

But the wealth tax will probably be a real threat in the not-too-distant future. America's long-run fiscal outlook is very grim because of a rising burden of government spending.

This necessarily means there will be a big fiscal policy battle. On one side, libertarians and small-government advocates will push for genuine entitlement reform. Advocates of big government, by contrast, will want new revenues to enable and facilitate the expansion of the public sector.

The statists will urge higher income tax rates, but sober-minded folks on the left privately admit that the Laffer Curve is real and that they can't collect much more money with class-warfare tax policy.

That's why there is considerable interest in new revenue sources, such as energy taxes, financial transaction taxes, and the value-added tax.

And, of course, a wealth tax.