Dying declarations can be admitted into evidence but they usually have to have concrete evidence which backs them up, or else anyone could frame a person they didn’t like and not have to face them in court.
Dying declarations were mainly from criminals who were confessing to a crime(s), often to clear their conscience before they croaked. Can be tricky, but also accurate.
This is what Scalia might have had in mind in his dissent.
That was king of what I was thinking, that there would have to be some kind of corroborating evidence.
And any evidence that contradicted the statement would necessarily be give very great weight.
But I can certainly see where there is a problem if the statement is an accusation and the person accused didn’t have a chance to cross examine him.
I’d be inclined to throw it out if it is accusatory of someone else. The reason being, these rights (right to confront the witnesses against you) were developed and put into place after years, decades of abuses.
And when you yield a little bit on one, then it just becomes easier to yield a little bit on the next one...
Next thing you know we are back to star chambers where you have no right to counsel and have no right to present exculpatory evidence.
IOW, your goose is cooked!