The subs attribute cannot be set on a compound block. It can only be set on a simple block. A simple block is a block that does not contain other blocks, such as a paragraph.
If I understand correctly, you want the output to be rendered as a quote block, but with callout numbers. That means you'll need to set the subs attribute on each paragraph that contains a callout number. You can use incremental subs to append the callouts substitution to the default set.
[quote,The Declaration of Independence]
____
[subs=+callouts]
When in the Course of human events it becomes necessary for one people to dissolve the political bands which have connected them with another and to assume among the powers of the earth, the separate and equal station to which the *Laws of Nature and of Nature's God* <1>
entitle them, a decent respect to the opinions of mankind requires that they should declare the causes which impel them to the separation.
[subs=+callouts]
We hold these truths to be self-evident, that all men are created equal, that they are endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty and *the pursuit of Happiness*. <2>
— That to secure these rights, Governments are instituted among Men, deriving their just powers from the consent of the governed, — That whenever any Form of Government becomes destructive of these ends, it is the Right of the People to alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness.
____
<1> Implies the founders believed in <a href="https://en.wikipedia.org/wiki/Natural_law[Natural">https://en.wikipedia.org/wiki/Natural_law[Natural law]
<2> The current American cultural conception of "Happiness" <a href="http://www.patheos.com/blogs/mercynotsacrifice/2013/07/05/property-and-the-pursuit-of-happiness/[tends">http://www.patheos.com/blogs/mercynotsacrifice/2013/07/05/property-and-the-pursuit-of-happiness/[tends more toward self-centeredness] which doesn't lead to true happiness at all.
Because it's an infrequent case...and exactly why the subs attribute exists.
Locked
Aug 02, 2018; 7:57pm
