Where did the term "soft core" come from, as in porn?

Matt:

Where did the term "soft core" come from, as in porn?

-- Jake, the net

No offense, Jake, but "soft core" is...um...the opposite of "hard core," dontcha think? But, hey, that's okay. That's what I'm here for. You start thinking, I'm out of a job. "Hard core" was originally an engineering term. Referred to a kind of stabilizing material used in building large structures like dams. In the figurative sense, probably from journalists and speechmakers, "hard core" was first used in the 1930s to refer to reactionary political factions and also to the "hard core of the unemployed." It was popular military slang in the '40s and '50s to refer to any tough son of a gun, a hard-core soldier. The first porn reference dates to 1947, in a U.S. Supreme Court decision on pornography. The prosecution had used the term to describe the offending material.

Satirist, publisher, Yippie, and general disrupter of the status quo Paul (The Realist) Krassner claims he coined "soft-core porn" around 1966, when he was writing for the anti-establishment publication The Independent. Since the courts have decided that hard-core pornography isn't covered by the First Amendment, Krassner reasoned, well, how about soft-core porn? The useful distinction is now a permanent part of our vocabulary.