The Laffer Curve is one of my favorite issues (see here, here, here, here, here, etc). But it is a very frustrating topic. Half my time is spent trying to convince left-leaning people that the Laffer Curve exists. I use common-sense explanations. I cite historical examples. I even use information from left-of-center institutions in hopes that they will be more likely to listen.

The other half of my time is spent trying to educate right-leaning people that the Laffer Curve does not mean that “all tax cuts pay for themselves.” I relentlessly try to make them understand that there is a big difference between pro-growth tax cuts that increase incentives for productive behavior and therefore lead to more taxable income and other tax cuts such as child credits that have little or no impact on economic performance.

Given my focus on this issue (some would say I’m tenacious, others that I’m bizarrely fixated), I was excited to see a column from the editor of a business paper in the United Kingdom about a tax increase that backfired in a truly spectacular fashion. It deals with the taxation of rich foreigners, called “non-doms,” who often choose to live in London because the U.K. government does not tax them on their foreign income. But then the Labor Party, with the support of spineless Tories, imposed an annual fee of £30,000 (about $45,000-$50,000) on these highly productive people.

The rest, as they say, is history. Here’s a long extract, but you should read the entire article.

Figures out last night confirmed yet again that crippling tax hikes are driving people and economic activity away from Britain. Rather than raising extra tax receipts to plug Britain’s budget deficit, there is growing evidence that the raids are actually reducing the amount of money collected by the taxman, thus inflicting even greater debt on the rest of us. Our predicament is depressing almost beyond words. The number of non-doms living in the UK collapsed by 16,000 in 2008-09, the most recent year for which data is available, according to yesterday’s figures. This is a dramatic decline: an 11.6 per cent drop from 139,000 in 2007-08 to 123,000. When in April 2008 Labour – egged on by the Conservatives – introduced an annual levy of £30,000 for those who had claimed non-dom status for seven years, pundits dismissed the tax as too low to make a difference. …Non-doms are people who originated overseas and pay UK tax on their UK earnings but no tax on their foreign income. The original non-doms were Greek shipping moguls who fled their socialist country to base themselves (and their businesses) in London. Until recently, the UK fought to attract such people; they pay a lot of UK tax and are often employers or high spenders. Yesterday’s figures actually underplay the true extent of the exodus: the departure of non-doms is bound to have accelerated in 2009-10 and will continue in the coming years as a result of the 50p tax rate, the hike in capital gains tax, the extra national insurance contributions and the near-hysterical war on financiers and myriad other attacks on wealth-creators and foreign investors that are now routine in this country. …The Treasury told us 5,400 non-doms opted to pay the fee. This means that the taxman raised an extra £162m. The Treasury wouldn’t or couldn’t give us any more information, so I’ve made a few guesstimates to work out the net cost of the tax raid. Being over-generous to the government, it might be that half the missing non-doms are now full taxpayers. Let’s assume they are paying an extra £15,000 in tax each. That would make another £120m in tax, taking the total to £282m. Let’s then assume that the 8,000 missing non-doms would have paid £50,000 each in UK income tax, capital gains tax, VAT and stamp duty – the gross loss jumps to £400m, which means that the Treasury is £118m worse off. The real loss is almost certainly much higher.

In other words, this is one of those rare cases where a tax increase is so punitive that the government winds up losing money. In a logical world, this should be an opportunity for the left and right to unite for lower taxes. The left would get more money to spend and the right would get the satisfaction of better tax policy. This assumes, however, that the left is more motivated by revenue maximization than it is by a class-warfare impulse to punish the rich. As Obama said during a Democratic debate in 2008, he didn’t care whether higher taxes raised more revenue.