help tracking down random SCOTUS quote Forum

[portaprokoss]

2 years ago I read a case (perhaps for jurisdiction, choice of law, or criminal procedure) where a justice said something like this:

"To demand evidence when obtaining evidence is impossible is merely to decide the issue." or "To require proof where proof does not exist is simply to assert your opinion." Something like that.

I know for certain it was a SCOTUS opinion . . . I've tried to track it down for 2 hours without luck. Does anyone recognize it?

[Gamecubesupreme]

Sounds like Iqbal or Twombly, not 100% sure though.