
Originally Posted by
Gimli2
This may be the wrong place but I was playing my HE campaign yesterday and it struck me why the SE and the HE aren't allies in the beginning? I mean if the HE are already allies with Eriabor why not the SE, given the fact Galadriel and Elrond are besties in the books and Elronds wife(from Lorien I believe?) and daughter spend a huge amount of time in Lorien which belongs to the SE in vanilla TA
While I in general concur with Finn's scepsisim on an outright alliance there is the case when Sauron was driven from Dol Guldur in 2941 (the year of The Hobbit) by a White Council military operation, to which our limited information should mean a joint Lórien and Imladris operation (I am curious but not hopefull to see what the movies will make out of it all hehe).
That the factions aint allied in TATW is presumably to increase the amount of interaction for the player (SE and HE are very likley to become allied, since they have same enemies and have Elven culture, anyhow) as well as because in SE Lorien and Mirkwood are combined, and Mirkwood was not allied with the High Elves - on the opposit they avoided them, that's partly why the Sindar leaders of the kingdom moved east to begin with, though there's been exceptions like when they joined the Last Alliance to stop Sauron.
If you want them to start as allies open data/world/maps/campaign/imperial_campaign and the file descr_strat.txt
Look for this;
Code:
faction_relationships egypt, at_war_with slave
faction_relationships egypt, at_war_with hre
faction_relationships egypt, allied_with turks
faction_relationships mongols, at_war_with slave
faction_relationships mongols, at_war_with hre
faction_relationships mongols, at_war_with england
and add this
Code:
faction_relationships egypt, at_war_with slave
faction_relationships egypt, at_war_with hre
faction_relationships egypt, allied_with turks
faction_relationships egypt, allied_with mongols
faction_relationships mongols, at_war_with slave
faction_relationships mongols, at_war_with hre
faction_relationships mongols, at_war_with england
faction_relationships mongols, allied_with egypt
Save and close.
Work in new campaigns 
(Possibly you have to open data/world/maps/base and there delete map.rwm before the edit kicks in, but don't think so)