Iakeo, that sounds a little bit like intellectual laziness, because we are, after all, discussing Objectivism, and on an Objectivism forum to boot. So, if you make a claim about an Objectivist viewpoint, you have to point out where it was said. And if you don’t state a view from an Objectivist viewpoint, you should state so from the outset, and then justify your position.
You said the government’s only purpose is to protect the Trader Principle. Please substantiate your claim, and your reasons for it.
Admittedly lazy, yes. 
I’m always, ALWAYS, uncomfortable stating anything I say as an “objectivist”
position or viewpoint. It really should NOT do that, as it’s not accurate.
What I say are MY viewpoints and positions, which should be obvious, but when I
do something silly like actually SAY that I’m representing the viewpoint of
some “collective” group, such as “objectivists”, I should expect people to become
confused.
Silly me.
The question is not so much “where” something was said (as I don’t have the
reference material handy), but whether what I said has any coincidence with the
principles of what is being discussed.
If someone is interested in what I meant by, as opposed to where I found, a
particular bunch of words, then asking me what I meant is called for. I’m simply
not interested in quoting other people to “justify” what I said, as I don’t consider
that justification.
It’s simply referencing a possible coincidence. It justifies nothing, as the meaning
is the important aspect, not the fact that "I said what <insert other person here>
said."
What is it that you think is the function of government?
I think the single function of a government is the enforcement of violations of
voluntary value for value (both parties regard the trade as a gain) transactions.
All proper governmental action can be derived from this principle.
The “right” of property, of the transacting parties, is implicit in this
system. “Voluntary” implies non-forced actions (prohibition of initial use of
force). “Value for value” implies something of value to trade held by the parties
(property).
A government performing any other function is simply unecessary, as all other
functions are better handled by individuals interoperating through voluntary value
for value transactions.
Other than a policing agency, to enforce “proper trading” (“the trader principle”,
this phrase being meaningless unless you look it up), and a sovereignty agency,
to enforce violations of the “nation’s” individual’s “proper trading” with individuals
of other “nations”, there is no need for any other function.
The “police” and “sovereignty” organizations are really just different “views” of the
same agency and function, thus my showing them as being under a single function.
Now, what was the question again..?
-Iakeo 