It's not dissimilar to what Rajoy has already done - require citizens to declare worldwide assets. This isn't a new tax, and only tax evaders have anything to worry about.
Hi - I think that the difference is that, in the case of the USA, the financial institutions are to be required to report on citizens' accounts, world-wide, direct to the Government! Currently, in Spain's case, isn't it the responsibility of the individual, alone, to give such info. to the tax authorities, on their world-wide assets? I'm not aware that, so far, Rajoy is demanding such info. direct from financial institutions abroad. But, will he..?
QUOTE/ A new law called the Foreign Accounts Tax Compliance Act (Fatca) will, from 1 July next year, require all financial institutions around the world to report directly to the US Internal Revenue Service (IRS) all the assets and incomes of any US citizens with $50,000 (£31,000) on their books. The US could withhold 30% of dividends and interest payments due to the banks that don't comply /END QUOTE
A point made in this news story is that the administrative process is a huge deterrent, so, perhaps it's incumbent upon the US tax authorities to ensure that their tax forms are simplified (please take note - UK inland Revenue..)!
Of course, tax evaders should be made to pay up = but, as a UK citizen, I'm well aware of the unfair taxation policies to which I'm currently subject. I know that the incredibly rich can afford to employ tax accountants with the expertise to enable them to avoid paying all of the tax due on their enormous wealth - whilst, in many cases, those tx evaders endorse the very political party which requires the general public to pay higher taxes!
Saludos,
GC