Assuming a traditional ethical pattern (such as those defined by the monotheistic religions that have dominated Western culture for some time), premise 2 is true. However, premise 4 does not logically follow, because premise 2 only states that "in MOST ethical situations, lying is a no-no." The question to be asked is this: how often is lying accepable in the context of a diplomacy game? To answer this question, let's examine the general times when telling falsehoods is deemed to be okay. Off the top of my head, there are 3 main situations:
1) The lie is told to diminish harm to another person, often called a 'white lie' (example: 'You look great!')
2) The difference between the statement and the truth is minor (example: 'I'll arrived at 4:00' when in fact you arrived at 4:03)
3) When the audience of your statement understand that you are not telling the truth -- this can be exaggeration ('There were a million people'), telling a joke ('That's what she said'), irony ('I just love it when my air conditioner breaks on the hottest day of the year'), etc.

I claim that all statements made in the context of a diplomacy game fall under situation 3.
Any intelligent player is aware of the fact that his opponents are attempting to win, and will try to act in their best interests, even when this includes lying to their fellow players. Thus, when player A tells player B 'I will support you into Rumania,' player B does not take this statement as a statement of fact, but rather as a political action. If this statement turns out to not correspond to the truth, player B will usually distrust player A's statements for a period of time. Thus, there is an disincentive to make statements that do not correspond to the truth. For a player who is acting in his own best interest to lie in diplomacy, he must be getting a large enough benefit to counter this disincentive. Therefore, a player is very unlikely to lie unless he plans a course of action that will be significantly better for himself than the course of action he claimed he would take.
Thus, when player A says 'I will support you into Rumania,' this should be viewed as a statement of fact. Rather, it should be viewed as player A creating a disincentive for himself for a particular action, namely not supporting player B into Rumania.

Player B does not trust the statement itself. Rather, he trusts that player A will act rationally within the bounds of the situation he is in, which includes a disincentive that player A himself has created.

no.

I said "most" and although i do not pull out survey's to prove it, i don't see the need to argue this point. Choose to believe it as you will.

I am actually not listing down premises 1-4, rather just points. 4 is actually a conclusion based upon premise 1 and premise 2.

anyway, not lying is not a sole purview of "western religion".

So basically you are assuming that telling a falsehood is always unethical, and then concluding that it's impossible to ethically win a game of diplomacy. Don't worry, maybe you can get to 2nd grade next year.

Because 2nd graders already know that you can't just make assumptions that are obviously equivalent to your claims if they want to be taken seriously.

chill man, i hope to get into 2nd grade next year too. Ms. Wormwood is killing me here.

Also, read my post carefully, especially where i say the words "it is said". The conclusion is not my own but what i observe that people are feeling. Hence the dichotomy between your interpretion of my post and my intention.

All diplomacy players always lie.

We don't lie! (is that an oxymoron??)

It would be more unethical to allow opponents to win by not lying to them.

If you make an alliance it is unethical to keep it. Funny.

Ethics? Diplomacy? Are we talking about the game whose central themes are based around something called a "stab"?

Seeing as Diplomacy is based on European diplomacy from 1900, lying should be a theme. Anyway, its a game, so, as long as youre not cheating, its okay. Lying doesnt hurt anybody in the game, so why would it be unethical?

i look at lying in diplomacy the same way as doing a feint in soccer, or baiting a queen in chess.

After all warfare is based on deception

I don't see what lying or stabbing has to do with monotheistic or western religions!! Am sure they existed and were indeed flourishing well before modern civilisation began to develop in the West.

My personal view is that stabbing or the use of deceipt in diplomacy is not more or less unethical than:
- a solider killing a fellow human in battle (from the other side)
- a banker making money at expense of another banker

It's part of the rules of the game, people should know what they have signed up for and the parameters within which they can operate.

i also have heard how people actually steal orders from another player before they get to the adjudicator (or do amendments)

is it within the "parameters"?

You can win without lying or metagaming. You just have to:

1) pick your statements and their wording carefully
2) speak without clarity

Well ethics are never black or white! I have heard rumours/articles of that type of behaviour going on in face to face play, which I'd personally find unacceptable and not within the parameters.

I'd consider it similar to someone being able hack into this site and view, change or delete orders from someone else they're playing against.

And if you're dealing with experienced players, you can just be honest or not talk about the issue of stabbing eachother at endgame as long as you don't tell them the timing of the stab.

Anlari: You might struggle against an ally who, each turn, presents you with a list of "sensitive" provinces, and asks you to explicitly confirm that you will not be moving into them.