Slavery wasn't the issue, Slavery was abolished since the birth of the country in 1824. Unlike Mexico, RFCA had cut ties with the Catholic Church and refused to pay tithe. Comparatively that took Mexico until 1920, after the Mexican Revolution to ban. Liberals were based out of Guatemala City the power of the RFAC (República Federal de Centro América) government was always limited the city and it's out skirts. The Liberals were lead by Fransisco Morazan a man revered by many Latin American leftist-thinkers as a foward thinker that had the mind to establish a Latin American Liberal Democracy in the early 19th Century. Morazan's issue is he was more of a reformist than diplomatic. The Conservative land owners opposed to Morazan became dismayed by his unrelenting drive to establish radical policies and ultimately raised armies and declared independence first Honduras (1838), then El Salvador. In 1842, Morazan died in San Jose, Costa Rica attempting to reunite the Ferderation. Since then reunification has been attempted 6 times, once even including the Dominican Republic. Yet those unions never lasted more than a couple years. Today the public will for unification is strongest ironically in Honduras, El Salvador, and Nicaragua. Yet the political situations that exist today in each individual nation, would never allow that.

EDIT: Another interesting aspect of Central American history is the war against Self-Proclaimed King William Walker. In 1855, a Tennessee Hick named William Walker that shows up in Nicaragua, which at the time was in the middle of a Civil War (Liberal v Conservative, it's typical of the 19th century in Latin America). He shows up with weapons and an army to wrestle control of the wealthiest town in Nicaragua at the time Grenada. Other nations in Central America become outraged that a foreign has invade a "brother" country and they all send armies to kill Walker. Walker at this point has already proclaimed the Kingdom of Nicaragua and he it's rightful ruler. Eventually a Honduran General by the name of Florencio Xatruch takes back the country and Walker's capital of Grenada is placed under siege. It takes a few months for the US Navy to evacuate Walker, and Nicaragua regains her rightful sovereignty. Xatruch's valiant effort is still seen today via how Central American's nickname Hondurans as Catrachos, a variant pronunciation of Xatruch. Other Nicknames are, Chapines for Guatemalans, Guanacos for El Salvadorans, Nico/a or Nicoyas for Nicaraguans, and Tico/a for Costa Ricans.

EDIT2: I'm looking for a historical map to add, FRAC included the present-day Mexican state of Chiapas, Belize, and the Panamanian Province of Chiriquí; along with the 5 present-day countries of Guatemala, Honduras, El Salvador, Nicaragua, and Costa Rica. Majority of present-day Panama was a part of Gran Colombia.

MAP OF RFAC, Author: BINET, MONIN & FREMIN , Date: 1836, Mislabeled as Guatemala.

EDIT3: would /r/historians mind if I elaborated and also included other aspects of Central American history? ex. The Legend of Tecun Uman & The Quetzal. It's a pretty bird!