Long after oil stops spilling from the Gulf and the ecological catastrophe caused by the spill begins to be cleaned up, the process of determining the extent to which BP owes the afflicted will be litigated in the courts. And while the case against the oil company seems fairly clear-cut (BP admits, after all, to being responsible for the worst environmental disaster in U.S. history), a lawyer with perhaps the most relevant experience on the matter at hand is painting a depressing picture about the litigation ahead. "f you were affected in Louisiana," said Brian O'Neill, an attorney with the firm Faegre & Benson, "to use a legal term, you are just f--ked." More than any attorney in the country, O'Neill personally understands the implications of that imprecise legal term. For more than two decades, he represented fishermen in civil cases related to the now second-most-damaging spill in U.S. history: the Exxon Valdez spill in 1989. And from it, he learned valuable lessons about how to sue an oil giant for the damages it has caused -- above all, to push for the best and plan for the worst. "In Valdez we had 32,000 legitimate claims -- that was a lot," he said in an interview with the Huffington Post. "I think there will be more claims in this one." "These big oil companies, they have a different view of time and politics than we do," he added. "The fact that BP hard-asses it a little bit for 5 to 10 to 15 years, despite all the bad publicity there may be between segments of society and BP as a result [of this spill]. Exxon sure weathered it really well. The market went up the next day for Exxon stock [after the settlement]. They just thrived despite treating an entire state poorly. And there is a lesson there for BP, and that is: it really doesn't matter whether you treat these people nicely or not. The only difference is if you extract oil. It sounds cynical but it might be true." The similarities between the two crises are telling in many ways. When Exxon's ship hit Prince William Sound's Bligh Reef -- in the process, releasing an estimated minimum of 10.8 million gallons of oil into the water -- the company pledged (like BP has done now) that they would cover the entire cost of the cleanup and all legitimate claims of damages. Two decades of litigation and appeals resulted in punitive damages being reduced from $5 billion to $500 million. The irony, as O'Neill tells it, is that the law Congress passed in the wake of that spill -- the Oil Pollution Act of 1990 -- may end up hindering the type of relief that Gulf residents can expect currently. Under that legislation, a $75 million cap was placed on economic damages that an oil company can pay as a penalty for a spill (this isn't true, O'Neill notes, in states that have passed their own liability caps -- of which Louisiana isn't one). Congress is currently trying to lift that cap. But there are constitutional questions about whether it can do so retroactively to cover BP. "Constitutionally, I don't know whether you can do that. I don't know whether it is ex post facto," O'Neill said. "It will likely be challenged. I would, if I was representing BP." There are other problems that the Exxon Valdez vet recognized when discussing the forthcoming courtroom battles for BP. There are questions, for starters, as to who actually can sue the oil company under the Oil Pollution Act law and whether, in fact, those 11 workers killed on the rig will have their settlements capped by the Death On the High Seas Act. Mainly, however, O'Neill is concerned over the pervasive influence that the oil industry has on all sector of governance -- which he predicts will weigh heavily on the legal process. "This is more important than banks," he said. "This is oil. And at some point in time, the administration and the states will resolve all their dealings and it will leave fisherman and the tourist industry to resolve their differences in the courts. It could be another 20 years till then because BP [is] going to defend this like Exxon did."