Here is how I rank the major powers. This does not count non corporeal beings. I have added done delta quadrant species in. This is how they stand around 2371. 1st tier( Galaxy spanning projection overwhelming military might) Borg Dominion (maybe between a 1 and 2 as the dominion can't go transwarp) 2nd tier ( large military might with diplomatic and economic influence over a large section of there quadrant) Federation Romulans Klingon Krenim imperium Devore 3nd tier (regional power with significant influence in there surrounding area) Tamarians ( maybe 2nd tier) Cardassian Ferangi ( I get the impression they are a economic power, however they have no centralised military instead relying on defence contractors and warships in private ownship with first line of defence being to useful to everyone) Breen Tholian Tzenkathi (they appear to have given the feds some trouble in a war) Bo'mar 4th tier ( regional power with limited influence) Gorn Talarian Talaxians Kazon Vidian Pakleds Lysian Satarran Mokra 5th tier ( single system civilisation with limited significance) Bajorans Acamarians Antedian Angosians Anyone care to add more?