This is a tricky question, but I believe there are certain cases where people living today have legitimate complaint for past wrongs, even if nothing overt has actually happened to them. Two groups come most readily to my mind--African Americans and Native Americans. Allow me to explain:
Since the first Europeans arrived (barring of course any Vikings who might have found their way across earlier than Columbus) Native Americans have been treated rather poorly, and have been systematically attacked on all levels, physical, mental, and spiritual. Likewise, Africans were brought to the New World as slaves--from the very beginning they were confined to the very lowest levels of existence. And a lot of people don't realize this, but there were very high numbers of Native American slaves as well--prior to 1720 Carolina exported more Native American slaves than it imported Africans (and probably the only reason Native American slavery declined was because about 90% of all Native Americans died from European diseases). Essentially, both Africans and Native Americans were reduced to squalor and held there for centuries.
Eventually, slavery was abolished in this country. And to hear a lot of people in this forum talk, that is where their "victimhood" ends. But were the former slaves repaid for what had been taken from them? Were they lifted back up to a reasonable level? Certainly not! All the US did was stop inflicting further crimes against them. The critical moment was in 1865, when General Sherman promised freed slaves "40 Acres and a Mule" as reparations for slavery. 40 Acres and a Mule was the foundation of a family farm, and would have, at least symbolically, restored to the former slaves the opportunities they had been denied. But then Lincoln was assassinated, and the promise was broken. The land granted to the freed slaves was returned to its former white owners, and slavery returned (in a less overt form).
Here is another way to explain it: imagine that I force you to carry a 200 lb weight on your back at all times. Wherever you go and whatever you do, you have to lug that weight around. At first you stand strong, but over time it gradually wears you down. Your posture worsens and your legs bow outward. Eventually, your spine curls under the weight, and you become permanently disfigured. Then, one day, I take off the weight and don't make you carry it anymore. Does me taking that weight off of you make us even again? Should I now expect you to walk just like me, with perfect posture and excellent poise? Of course not--I inflicted lasting harm on you. Unless I pay for surgery to repair the damage I inflicted, you will probably never walk normally.
As I said, this is a tricky question, because unlike my example there have been many generations since the weight was removed. Do the descendants of slave owners owe something to the descendants of slaves? Most people would answer no, but we must acknowledge that the current social order was built on oppression and theft. If I buy a stolen car, even if I have no knowledge of or connection to the theft, that car is not truly mine.
This is precisely the dilemma that confronts us: white America is in possession of stolen property (the land was stolen from the Native Americans, and a great deal of wealth can be traced back to the time of African slavery), and Native Americans and African Americans are still suffering because of the loss. But the thieves, the ones who are directly responsible, are long dead. They cannot pay, and they cannot be punished. What is the correct solution?
I don't really know the answer, but my response would be this: why are we so worried about assigning blame and responsibility in the first place? These people are suffering from unjust circumstances, and many of us have means to spare. Shouldn't we try to help them simply because we are a civilized society and want as many people as possible to reach their full potential? How many geniuses have we lost to violence and neglect in the ghetto and in prison? We like to think that true geniuses will rise regardless of their circumstances, but that is a myth the people who made it like to spout because it makes them seem even more amazing. For every rags to riches story there are probably 1000 people who were just as brilliant but whose brilliance was never seen because they had to drop out of school and spend their time working at McDonalds to pay for their crippled parent who was injured without health insurance and their siblings who spend all day living next to drug dealers and prostitutes and getting shot at on the way to school. This isn't sad just for the people who never get the chance to shine. It's sad for all society that is denied the benefits of their brilliance.