Liberty means no ex post facto laws. Earnings made before passage of any such law (which, let's face it, will NEVER pass with the current Congress - whether you agree with them or not) should be excluded from this. If the Government can retroactively tax your profits,
This isn't a retroactive tax.
There's no ex post facto involved.
You see, the trick is that technically, all the money held overseas is deferred income.
The IRS said "you don't have to pay your taxes until you bring the money back to US shores."
The corporations said "Cool, we'll bring it back. No really, we will. But how about we pay you less when we bring it back?"
As a result, the incentives for repatriating foreign profits are completely upside down and backwards.
It makes far more sense to dodge US corporate taxes and invest the money overseas.