Constitutionally

Con`sti`tu´tion`al`ly

adv.	1.	In accordance with the constitution or natural disposition of the mind or body; naturally; as, he was constitutionally timid. The English were constitutionally humane. - Hallam.
	2.	In accordance with the constitution or fundamental law; legally; as, he was not constitutionally appointed. Nothing would indue them to acknowledge that [such] an assembly . . . was constitutionally a Parliament. - Macaulay.

Adv.

constitutionally - according to the constitution; "this was constitutionally ruled out"

Antonyms:

unconstitutionally - in an unconstitutional manner; "the president acted unconstitutionally"