[JohnFen]

The President isn't "head of government". He's the head of the executive branch. He's not in charge of the other two branches.

[nix-zarathustra]

The President is effectively Head of Government, since he can veto any bill (unless rare ocassion that congress overrules, but requires large majority). The President basically sets the agent for policy about what can get passed in congress because of this.

[epc]

I know, but outside the US the role is considered head of government.