1713 Do you really mean this?

Today I noticed a letter where the writer was describing the wonderful attributes of Janice Rogers Brown, the black judge many of us would have preferred to Alito:

“When you read her speeches, it becomes crystal clear that she is worth fighting for, to go to the mattresses for, to the very end.”

I think he meant “go to the mat” not mattress.

But upon checking, I learned this mangled cliche is not that uncommon.