A military coup aided by the CIA took over the Guatemalan government. This caused extreme backlash from the left, which lead to guerrilla warfare. The civil war was so bad that the United Nations accused the Guatemalan government of genocide against people of Mayan descent.
The skirmishes in Honduras were less bloody than the civil wars of El Salvador and Guatemala, but they did put the country into extreme poverty. The government in Honduras was already extremely weak, but after the skirmishes, they were even weaker. The skirmishes were not bloody enough to make many people flee, so Hondurans cannot be blamed for starting the violence. However, as an aftermath of the battles, guns became extremely cheap and gangs could easily get ahold of them
The El Salvador Civil War was almost exactly like the Guatemalan civil without the genocide. It was extremely bloody and caused many people flee to the United States.
Salvadorans in particular were extremely discriminated against because of their race. Gangs had already begun to form in Los Angeles to protect African Americans against discrimination, and Salvadorans and Guatemalans saw that it worked to protect themselves against racism. Violent gangs of Salvadorans and Guatemalans began to form in Los Angeles
Even though people no longer needed to flee war, El Salvador did not become a safe place to live. As an aftermath of the war, the government was extremely weak. Many Salvadorans had been displaced. The civil war made the country very unstable.
Many of the people who fled the civil war were illegal immigrants in America, so many of them were deported by President Bill Clinton. He wanted to rid America of dangerous people, and many of the illegal immigrants were a part of the violent gangs that had formed. The deportees took the violent gang culture they had learned in Los Angeles back to their native countries with them. The weak governments of Guatemala and El Salvador didn't know what to do with them.
The civil war finally ended after 36 years. By the end of the war, over 200,000 Guatemalans had been killed, with 82% of them of Mayan descent. According to the United Nations, over 93% of human rights had been violated by the Guatemalan government.
Gangs first began to emerge in El Salvador and Guatemala since it had been Guatemalans and Salvadorans who had learned gang culture. Since Honduras was weak and guns were cheap, gangs seized the opportunity to spread there.
In early 2001, a 7.6 earthquake struck El Salvador, destroying much of what had been rebuilt after the civil war. The earthquake sent the country further into poverty and continued to weaken the government.
The Salvadoran government tried to put a stop to the gang violence, so they wrote up a truce. The two biggest rival gangs, Barrio 18 and MS-13 street gangs, agreed to sign it. The Salvadoran government did not have enough power to strictly enforce the truce, but it was a step towards ending the violence.
The Salvadoran government was too weak to make the gangs obey the truce. The government could not stop the violence, so they overturned the truce. Since the truce has been overturned, the violence has skyrocketed, but the government has not yet made another truce.