gameObject.tag == "Respawn"; won't do anything...

This was supposed to be easy but it's giving me a headache:

I have a simple untagged cube made by Unity.

I attach to it the following script:

function Awake (){
    gameObject.tag == "Respawn";
}

Respawn is in the tags list (by default).

When I hit "play", shouldn't I see the cube's tag field in the Inspector change the display from "Untagged" to "Respawn"?

No change happens. The tag field continues to show "Untagged". What am I missing here?

It should be:

gameObject.tag = "Respawn";

== should really be throwing a warning at you