http://en.wikipedia.org/wiki/Colonization
Colonization (or colonisation) is the act where life forms move into a distant area where their kind is sparse or not yet existing at all and set up new settlements in the area.
http://en.wikipedia.org/wiki/Colony
And just about every European colonization attempt would have started out as a counter-example too.
I disagree - I think most colonies were started in sparsly populated areas and...
http://en.wikipedia.org/wiki/Spanish_Empire
Native tribes were usually at war with one another and some of them were only too willing to form alliances with the Spanish in order to defeat powerful enemies, such as the Aztecs or Incas
And thus the war by proxy rule is covered.
I don't know if I would use the colonizing of the New World as a true historical example against. The European powers did not just show up one day and declare war. They established their colonies and then expanded out and into the native peoples.
I agree.
BTW - sealman, great description of almost every war in civ3. Another BTW - what side are you on exactly

you waffled at one point and i am unclear on your current status.
For the most part, I think that feature that can be turned on or off is a feature that need not be implemented.
I disagree - I think nearly every rule should be optionable... if there is scoring for HOF involved and a point multiplier for all the harder rule options.
It is true that long distance wars have occured throughout history, but these wars were generally over tangible reasons
I agree Heat Mizer - good points. Its really not my point that the rule I am suggesting is realistic or not (though I think it is more often realistic than not by far), its more about making a better more interesting game.
The Chinese and Huns were separated by deserts and dozens of small countries, and yet the Chinese destroyed the Huns. Craterus22's idea would place an un-needed restriction on gameplay, which is both no fun, and a gross violation of historical accuracy.
dida - potentially good example (i think-still reading up on it) of an early war without border issue. I don't agree with your conclusion that it would not be fun and that it is a gross violation though...
Could some of those states that refused an alliance be the ones referenced below?
http://en.wikipedia.org/wiki/Han_dynasty
Non-Chinese states were allowed to remain autonomous in exchange for symbolic acceptance of Han overlordship
Could they have been defacto subjecct states that were allowed to remain "autonomous" until it was deemed inconvenient?
http://en.wikipedia.org/wiki/List_of_wars
Haven't found that particular war on the list at wiki -
Found this quote after a google search though:
http://boards.historychannel.com/thread.jspa?threadID=300030544&messageID=300438975&start=15
First of all, the Han Dynasty ruled China while Rome was in power. Around 100 BC, Emperor Wu Di "the martial emperor" launch a massive campaign to rid China's northern borders of Hsuing-nu or the Huns. Under Wu Di, China field a very large highly disciplined professional army.
Huns on the border or not? Ouch... your making me research and learn - darn you all to heck!
As a game mechanic - I think border touching or nearness could make the early game better on a number of fronts - JMHO. Thanks to everyone for the discussion.