The unyielding growth of rules, then, has persisted through Republican and Democratic administrations (see chart). Several factors explain it. First, Congress has neither the staff nor the expertise to write complex, technical laws. So lawmakers happily let experts in government agencies fill in the blanks. What Congress does write itself, it writes sloppily. In 2015 the Supreme Court found “more than a few examples of inartful drafting” in the Affordable Care Act. One such error nearly saw the court strike down crucial parts of law; only semantic gymnastics saved it. The “Chevron deference”, a doctrine from a 1984 court ruling, gives agencies wide latitude to interpret laws when they are vaguely written. (Neil Gorsuch, Mr Trump’s nominee to the court, is not a fan.)
What's the meaning of that above sentence in bold? Thanks!