Never trust who doesn't trust you.
That's mine.

Location, location, location.

Any more for any more?

I disagree with that one hellalt. I often distrust people whom I have no intention of betraying.

I heard something that went like: "If you leave a SC undefended from a friend, you are trusting an enemy".

Here's some of mine:-.
"Curse your sudden but inevitable betrayal!" - Wash, pilot of the spaceship Serenity. from the TV series Firefly.

"Diplomacy: The art of saying ´Nice Doggy´ while finding a big stick." - Robert Heinlein.

"We must acknowledge, once and for all, that the purpose of diplomacy is to prolong a crisis" - Mr Spock, "The Mark of Gideon", Star Trek (TOS)."

"Trust, but verify"

damn, I was going to go with the Regan quote - stratagos beat me to it. Although in the game Diplomacy, I alter it slightly to "Trust, but defend"

ok here's one I've always liked:
“Diplomacy is the art of letting someone have your way.”

"Diplomacy is warfare carried out by other means"
- Carl von Clausewitz

And for those who would contradict me... I know, but I think this is a logical corollary.

Who is Regan, philcore?

Seriously? And I thought you were a scholar of american history ... Donald Regan was the 66th Secretary of the treasury, of course. He was a Marine in WW 2, served in Guadal Canal and Okinawa as a Lt Colonel, later ran Merill Lynch, before becoming Secretary of the Treasury under a guy who's name was erily similar. Some actor from the 50's named Ronald Reagan.

He was famous for saying "trust but verify" refering to the investors' margin accounts at Merril Lynch

Seriously? And I thought you were a scholar of American Litterature ... Judith Regan is a well known publisher with Simon and Schuster who's credits include "The Zone" by Barry Sears, "Stupid White Men" by Michale Moore and "Private Parts" by Howard Stern.

She was famous for saying "Trust but Verify" refering to manuscripts submitted to her. She was a stickler for finding mis-spellings!

Keep 'em coming one and all.

“The principle of give and take is the principle of diplomacy - give one and take ten” - Mark Twain

Umm... duh:

"All warfare is based on deception"

Sun Tzu

Also there is "know your enemy"

and "keep your friends close, but..."

and "those who live by the sword will die on its edge" -Christ

and "with friends like these, who needs enemies"

oh and of course, israel to lebanon:

"Cluster bombs? What's a few cluster bombs between friends?"

Brillaint stuff so far, give one and take ten, love it.

"To say nothing, especially when speaking, is half the art of diplomacy." I'm not sure who said it. I got it from a friend.

Here, have some from Machiavelli especially useful in Diplomacy. And sorry about the bad english.

"Men should either be favored or anihilated (...) The offense made to a man must be in such a way as not to fear revenge from him"

"War cannot be avoided, only delaying to the benefit of others".

"Never in times of peace be idle"

And one from Lincoln that you can use if for some reason you want to make the person you just stab even angrier: "Bad promises are better broken than kept".

*read "delayed" instead of "delaying", of course.
*and "stabbed"...

My brother was distracting me (on purpose, too)...

"Never start a land war in Asia"

Also: "I must study politics and war that my sons may have liberty to study mathematics and philosophy"

Damn I was about to use to John Adams quote.

"People are more inclined to believe a big lie, then a small one" Adolf Hitler (translated)

"If you want peace, be prepared for war" Latin Saying (translated)

The man who has confidence in himself gains the confidence of others ~ Hasidic Proverb

Not really a diplomacy quote, but my favorite quote ever:

Only two things are infinite, the universe and human stupidity, and I'm not sure about the former. - Albert Einstein

It applies to diplomacy quite regularly, though.

"If you can keep your head when all around you are losing theirs, then you probably haven't understood the seriousness of the situation"

"You can get more with a kind word and a gun than with just a kind word" Al Capone
"Keep your friends close and keep your enemies closer"
"If you attack two countries you will be defeated by them both" (My own variation on "If you chase two rabbits you will lose them both.)

The pen is mightier than the sword, but only if the sword is very small and the pen is very sharp. - Terry Pratchett

When a diplomat says yes he means perhaps; when he says perhaps he means no; when he says no he is no diplomat.

"A diplomat...is a person who can tell you to go to hell in such a way that you actually look forward to the trip."

Gentlemen, in the little moment that remains to us between the crisis
and the catastrophe, we may as well drink a glass of champagne.
- Paul Claudel.

One should forgive one's enemies, but not before they are hanged.
Heinrich Heine (1797 - 1856)

ad infinitum.....

If one does not know to which port one is sailing, no wind is favourable ~ Seneca
The man who has confidence in himself gains the confidence of others ~ Hasidic Proverb
Count not him among your friends who will retail your privacies to the world ~ Publilius Syrus
He who does not know how to be silent will not know how to speak ~ Ausonius
Never guess. It is a capital mistake to theorize before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts ~ Arthur Conan Doyle
The man who chases two rabbits, catches neither ~ Confucius