NASA must build rocket, not Congress, editorial, Sun Sentinel
"Congress did, fortunately, leave NASA a loophole. The bill says the space agency must use existing elements of other programs "to the extent practicable." That leaves NASA some room to make its own decisions. It should, however, use that wiggle room cautiously, ever mindful that Congress may look for other ways to meddle in NASA's work. When you have 535 meddlers, expect meddling."
NASA technology chief: We'll decide what rocket we want to build, Orlando Sentinel
"But the legislation leaves a large loophole for NASA engineers. While it encourages NASA to use existing parts, it is says only "to the extent practicable." In other words, if NASA decides it is not practical to use solid rocket motors, it doesn't have to."
"However, the bill is not a perfect strategy. I remain concerned with the limiting direction set forth on the heavy lift rocket's design. NASA must not deliver a rocket that is simply a shuttle without wings. This would not represent a step forward for innovation or for the future of our space program."