As legal challenges loom for new net neutrality regulations, GOP members of the Federal Communications Commission are offering some of the first lines of attack. The dissenting opinions of the two Republicans ran 80 pages, and they telegraph some of the arguments on which critics could rely as they prepare legal filings to scrap the new rules. FCC Chairman Tom Wheeler has repeatedly said the commission wrote the rules to withstand challenges from the “big dogs.” And while it is still unclear which organization or company will lead the charge, there is little doubt that a legal battle is...