[pattisapu]

Sorry if this is a dumb question -- but what would be the motive for a sitting justice to leak a draft?

To test what celebrations or outrage would happen in the streets, maybe?

If they are that concerned with public opinion -- which they shouldn't be, but say they are -- I would think that would incentivize even stronger efforts to maintain confidentiality and discretion.

(Maybe you didn't suggest that it was intentional, but an accident. Even then I might wonder why someone would let their guard down on this case. Maybe there was so much more work done on one particular case, people get physically tired, etc.)

[pseudalopex]

Judges don't want people to believe public opinion can change decisions. Leaking a draft discourages judges from changing their votes or negotiating other changes.