The Andorian Empire was a parliamentary democracy, lead by the Andorian Chancellor. The Andorian Chancellor maintained diplomatic relations with the Aenar race, following their contact in the early-22nd century.
The military branch of the Andorian Empire was known as the Andorian Imperial Guard, which operated both starships and infantry forces. After the founding of the Federation, many Andorians served in Starfleet.
Conflicts with Vulcan
The Andorian Empire went through a period of numerous conflicts with Vulcan, due to their neighboring home systems and the Vulcan suspiciousness towards the territorial and militaristic nature of the Andorians.
In the mid-21st century the Andorians terraformed a Class D planetoid which they named Weytahn, lying at a strategic position on the frontier between the Andorian and the Vulcan system. When Andoria refused to allow the Vulcan High Command to inspect the colony in order to search for possible threats in form of military installations, the Vulcans forcibly evacuated the planetoid. In 2097, a treaty was signed, in which the Vulcans officially claimed Weytahn, which they named Paan Mokar, and a surveillance satellite was placed in orbit of the planetoid in order to enforce the accord.
In order to guarantee the safe "observation" of their "aggressive" neighbor, however, the High Command maintained a highly sophisticated surveillance station beneath the monastery of P'Jem close to Andoria. Using the disguise of an ancient Vulcan monastery, the facility was able to spy the Andorian population while staying unnoticed. In 2151, Shran, a Commander in the Andorian Imperial Guard, unveiled the secret of P'Jem with the help of the crew of the Earth starship Enterprise, thereby starting Human-Andorian relations and dealing a crippling blow to Vulcan prestige. After the Andorians destroyed the monastery later that year, however, the High Command began blaming Starfleet and Subcommander T'Pol, who was serving aboard Enterprise, for the loss of P'Jem, which would not only result in T'Pol's mother being expelled from the Vulcan Science Academy but also in an impairment of the Human-Vulcan relations.
Another hotspot in the cold war between Vulcan and Andoria was Coridan, a Class M planet rich in dilithium ore. In the 2150s, Coridan suffered from a civil war, in which rebels, backed by the Andorian Imperial Guard, tried to overthrow the chancellor and her corrupt government, who was in turn supported by the Vulcan High Command, since Vulcan tried to maintain its trade partnership with Coridan, which was a lucrative source for dilithium.
In 2152, a new open conflict arouse on Weytahn, which was reclaimed by the Andorian Empire after being deserted for nearly 60 years. With the conflict about to escalate, Shran, who was leading the Andorian invasion forces on the planetoid, requested Captain Jonathan Archer of the Enterprise as a trustworthy mediator in order to negotiate a cease fire, which could finally be accomplished and both sides resumed their negotiations.
Member of the Federation
After further years of mutual rapprochement, the Vulcan-Andorian conflict eventually came to an end with the foundation of the United Federation of Planets in 2161, of which Earth, Vulcan, Andor and Tellar were the founding members. However, a few rogue Andorian factions chose not to join the Federation, and continued to be a threat to Federation starships even in the 24th century.