Are Overdue Apologies Ever Worth It?

America apologises for Hiroshima – well, sort of. It recognises the suffering caused – well, kind of. A US ambassador attended a memorial ceremony yesterday in Hiroshima... but don't confuse that with saying "sorry".If you apologise for killing civilians, you have to do it quickly and for humanitarian reasons. Wait too long or do it for political reasons, and it loses its effect.
Today many believe the atomic bombings of Hiroshima and Nagasaki were "war crimes". And the attitude at the time, that the bombs spared a bloody Allied invasion of mainland Japan, skirts the fact that the bombs mostly killed civilians.
So then, will Japan apologise for the murder and rape of a million Chinese civilians in the attack on Nanking before WWII? Will it apologise for Pearl Harbour? 
And really, what good does it all do? In 1997, Britain's PM Tony Blair recognised the suffering of the Irish potato famine victims, saying the government did not look after its Irish citizens...even though the famine took place 150 years ago! Note: no apology. Then the Brits waited almost 30 years to say sorry for the Bloody Sunday killing of 14 civilians by British paratroopers. Had the truth been told at the time, Northern Ireland's civil war may have been far less bloody, but the lies helped IRA recruitment. Even now, USA and its tag-team show no intention of apologising for the illegal 2003 invasion of Iraq. And here in NZ, the public purse is constantly raped for cash apologies to maori tribes, over colonial errors of the 1800s.
Hiroshima is a symbol for mankind's guilt, but it raises the question: do "war crimes" and colonisation heavyhandedness have an expiry date? If not, what about 1066? Or the Spanish brutalities in South America? Or even the death of Jesus? I guess Italy would have to apologise for that...and then lots of Christians would need to apologise for blaming the Jews.
Yeup, its a thorny issue, this 'post-dated apology' business. Is it a step in the right direction? Or far too late?
PS: 11 August 2010 - Surprise-surprise! Japan has apologised for the 1910-1945 occupation of the Korean peninsula, while quickly adding it's not willing to discuss any compensation claims!