Preamble vs Purview

horizontal closeup near surface of all-white puzzle with a piece lowering into place casting its shadow below it

​The Preamble (proposed for restoration):

"We the People of the United States,

in Order to form a more perfect Union,

establish Justice,

insure domestic Tranquillity,

provide for the common defence,

promote the general Welfare,

and secure the Blessings of Liberty to ourselves and our Posterity,

do ordain and establish this Constitution for the United States of America." 

Our Preamble is actually a purview. Come again?

A purview is the part of a law that states in general what it does, and that enacts itself as a law with an enacting statement:

'We do do this' says 'we commit this act right now, by this sentence'. A law is an act.  

"We the People of the United States do ordain and establish this Constitution for the United States of America"

is an enacting statement.

When a law doesn't require ratification an enactment,

an affirmed signature and the date are all it needs to become enforceable.

When ratification is required an enacted law is a proposal. 

(A preamble, by contrast, states history, purposes and intent:

'We're going to do this' doesn't enact but only states intent. A preamble does not include an enacting statement.)

The affirmed signatures and date complete the law's enactment.

The signatures complement the enacting statement's 'We do do this' with 'This has been done by us'.

"Done in Convention by the Unanimous Consent of the States present

the Seventeenth Day of September

in the Year of our Lord one thousand seven hundred and Eighty seven

and of the Independence of the United States of America the Twelfth

In witness whereof We have hereunto subscribed our Names."