null constraints and defaults

It seems that the not null constraint is applied
before the default constraint if a column is
defined with both default and not null.

I understand that default should make the
the NOT NULL constraint unnecessary. But still....

Is this the intended behaviour?

create table nulldefault ( one integer NOT NULL default 1 );
CREATE TABLE
^
elein=# insert into nulldefault values (NULL);
ERROR: null value in column "one" violates not-null constraint

elein=# create table defaultnull (one integer default 1);
CREATE TABLE
elein=# insert into defaultnull values (NULL);
INSERT 4681559 1

--elein
elein(at)varlena(dot)com