Law360, New York ( July 9, 2015, 12:23 PM EDT) -- Claim construction is just about the most important part of a patent lawsuit. And when it comes to a prior art invalidity challenge, the standard used to decide just how broad patent claims are can be the deciding factor on whether a patent is valid or invalid. So it should come as no surprise that there is a healthy debate going on regarding the Patent Trial and Appeal Board's use of the broadest reasonable interpretation standard for claim construction; a standard that on its face purports to be broader than the Phillips standard for claim construction used in federal district courts. This criticism is now at a focal point, with the Federal Circuit split 6-5 on the issue and a number of pieces of legislation attempting to make their way through Congress. Below we take a look at how we got here, the Federal Circuit's division, the progress of efforts in Congress to change the standard going forward, and the U.S. Patent and Trademark Office's response to criticism....