Nobody mentioned tobacco last week when the U.S. Senate adopted an amendment to the $109 billion federal highway bill. But tucked into the 5,600-word amendment to provide aid for rural schools was a single paragraph that would settle a two-year-old fight between Big Tobacco and a small Ohio company that builds a do-it-yourself machine that allows smokers to get their cigarettes a lot cheaper. The amendment would reclassify tobacco shops that offer the machines as “tobacco manufacturers,” imposing on them new regulations and higher taxes, and it opens a window into the ways of Washington, where the powerful and the...