Loli will never be illegal in the states because the simpson movie had bart's dick exposed briefly. If they went and made loli illegal and equal to cp, then everyone with a copy of the movie would automatically be charged with possessing cp. Not to mention every single server having to scrub the entire movie
the reason lolicon isnt oft prosecuted against is because the justice system knows its opening a can of worms with those subjective meanings of "artistic" and "political value", so they really dont press charges except for people who have actual cp as well, or for people who are known to rape kids