[2009 Tax Amnesty passed by] 111th Congress. You know, the one that had Democrat majority in both the House, Senate
Lol. So it's the Democrats fault!? The whataboutery-foo is strong in this one. You think they should not have permitted the amnesty? And put the criminals in prison?
if it's amnesty, then how is what happened then exactly illegal?
I guess you don't understand what amnesty means? To re-cap : following a leak by a whistle-blower, Swiss bank UBS gets sued by the US to release their full list of tax criminals' names. The IRS is more interested in the money than putting thousands of the rich and/or famous behind bars, so offers an amnesty - those tax evaders who voluntarily fess up, report their fraud and pay what's due are not prosecuted.
The tax evasion was and is illegal. Amnesty from prosecution does not magically make the previous behaviour legal. And even if it did, the issue for Romney, if the allegation is true, is that he willfully and deliberately committed massive tax fraud, knowing at the time that it was illegal. That is massively damaging whichever side of the fence you're on. (And by the way, I don't really have a horse in this race because I'm not permitted to vote in that election. If I could vote, I cannot imagine that I would be persuaded to vote Obama).