One of President Barack Obama’s biggest legacies will be his healthcare plan. Another, thanks to the Edward Snowden leaks, is domestic spying. But Obama has another legacy, one not so obvious, and which won’t be felt until years after he’s left office. The history e-books will remember the 44th president for setting off a chain of reforms that made predatory patent lawsuits a virtual memory. Obama is the patent-troll slayer.