Support for the guerrilla cause can quickly dry up:

The continued agonizing over the May 5 killings was apparent during Greece’s latest general strike on Thursday. Roughly 20,000 union members marched through Athens, a fraction of the more than 100,000 who took to the streets the day of the murders. In the end, the anarchists also took part in Thursday’s protests, but turnout was modest, and those who did participate were peaceful.

“It’s a shock. We always thought of ourselves as people who are victims, not people who create victims,” says Panagiotis, an edgy 30-year-old who helps organize cultural events within the anarchist scene and condemns the killings. Like most members of the movement, he would only gave his first name.  “In Greece, Anarchy Yields to Soul-Searching,” Marcus Walker, Wall St. J., 22 May 2010.

As I noted in COIN, tight integration of guerrillas and people is critical if the cause is going to survive.  Otherwise, the public will — correctly — view the guerrillas as thugs and criminals.