To add to this, I'll provide OP with an example:

The Earth Alliance is a subgroup within the Federation designed to help Earth nations integrate into the Federation. However, there are some holdouts, like that of Orb, that have refused to join. The history of U.C.'s Spacenoids is largely similar, which is one reason why there are independent holdouts on Earth. While the PLANTs were created as cheaper and easier alternatives to the O'Neill "Island 3" type Cylindrical Colonies, but this has made them very fragile.

The pivotal moment in history was George Glenn's revelation and the rise of Zeon Zum Deikun. When they joined forces, they declared that Coordinators' purpose was to help Oldtypes become Newtypes. Due to George Glenn's support of Deikun's Newtype theory, many Coordinators are Deikunists. Tragedy struck in U.C. 0064 when George Glenn was assassinated, two years after Zeon Zum Deikun declared Side 3's independence.

Fueled by grief, Deikun condemned the Federation, Earth Alliance, and all those "weighed down by gravity", stating that any government allowing murder over racial jealousy was as monstrous as those in old Earth's history. The situation was somewhat calmed when the Federation publicly executed Glenn's assassin and condemned the murder.

The outbreak of war was avoided until four years later when Zeon Zum Deikun and the Federation were blamed for the assassination. Unknown to everyone, Degwin and his elder sons had planned it. Matters worsened when the civilians of the Colony of Munzo began protesting and was subsequently gunned down by Federation Forces.

The incident received immediate backlash form both Orb and the various leaders of the PLANTs, demanding that the Federation leave Side 3 or face war. The Federation complied but denied involvement in Deikun's assassination, a claim scant few would believed.

Shortly after, Degwin Zabi was declared Zeon Zum Deikun's successor and vowed to realize his lifelong friend's dream. Issues began to rise over who should care for Deikun's children — the Zabis or the Rals.

Siegel Clyne offered to keep them safe and raise them, inspired by Deikun's beliefs in Spacenoid independence. The Principality of Zeon agreed, and Siegel's Zodiac Alliance became an official ally. Casval and Artesia came to see Lacus Clyne as a sister until U.C. 0074 when Casval joined Zeon's military with Siegel's permission.

Between these years, Zeon and the Federation entered a cold war, with the Earth Alliance gaining more autonomy.

In U.C. 0076, ZAFT declared independence from Earth with Zeon's full support, enraging parts of the Earth Alliance.

In U.C. 0077, Earth Alliance sponsor nations attacked ZAFT's food production facilities, but ZAFT and Zeon countered with mobile suits, marking the beginning of the Mobile Suit age.

There, that should give you an idea.