Is one who is drunk obligated in Tefillin?[1]

No.[2] If one is drunk to the point that he cannot speak coherently before the king, and is hence exempt from Davening, then he is likewise exempt from Tefillin, and it is forbidden for him to wear it.

[1] Piskeiy Teshuvos 38:7

[2] So is clearly learned from the above Halacha which exempts the entire group of wedding participants from Tefillin due the fact that drunkenness is common.