The following is a quote from Wikipedia (above link) on non-violent direct action:
Nonviolent direct action (NVDA) is any form of direct action that does not rely on violent tactics. Mahatma Gandhi's teachings of Satyagraha (or truth force) have inspired many practitioners of nonviolent direct action, although the use of nonviolence does not always imply an ideological commitment to pacifism. In 1963, civil rights leader Martin Luther King Jr. described the goal of NVDA in his Letter from Birmingham Jail: ‘Nonviolent direct action seeks to create such a crisis and foster such a tension that a community which has constantly refused to negotiate is forced to confront the issue. It seeks so to dramatize the issue that it can no longer be ignored.’
“One major debate is whether destruction of property can be included within the realm of nonviolence. This debate can be illustrated by the response to groups like the Earth Liberation Front and Animal Liberation Front, which use property destruction and sabotage as direct action tactics. Although these types of actions are often viewed as a form of violence, supporters define violence as harm directed towards living things and not property.”
The peaceful January 13th demonstration in Riga—which began at 5:30 p.m. and ended at 7:00 p.m.—was followed up by youths marching to the Saeima building and pelting it with snowballs and raw eggs. Cobble stones torn from the street followed.
Up to this point—if we go by Wikepedia and the exclusion of damaged property as a sign of violence as argued by ELF and ALF (see above quote)—one may argue that the police acted right by leaving the Saeima building door guarded by only eight policemen and leaving support forces out of sight.
If I heard the news right, the police say that at some point “later” there appeared a gang of provocateurs in black leather jackets, who started throwing cobblestones in all earnestness, which is when the police intervened in earnestness.
Whichever act one understands to be the limit of non-violent direct action, the discussions of the protest in the Latvian media make clear that the Latvian media and the public have little idea what non-violent direct action is—which makes the discussions in the media of the event a muddle, uninformative, and potentially disruptive of peace.