Even if the marches pass without sustained violence or terrorist attacks, the effort to arrange a political settlement must still overcome many obstacles.

The Neo-Whigs have difficulty explaining a tipping point from mild protest to sustained violence.

The August riots were the most sustained violence that Northern Ireland had seen since the early 1920s.

The thrust of many speeches, however, reflected the sustained violence across the land, often pitting black against black.

The war's coldness and cruelty help explain the sustained violence in the work of Andre Masson.

Police struggled to cope with multiple outbreaks of looting as well as sustained violence in several places, most notably on an estate in Hackney.

"But increased drug production and trafficking, coupled with a serious economic recession and sustained violence, have put that progress in peril."

It will, more than anything, have been the inevitable climax to a late 20th century nightmare of sustained violence perpetrated by athletes against women.

It includes sustained, thunderous, disturbing violence and nasty casualties, most of which occur off camera.

A prerequisite for peacemaking is for antagonists to realize that good-faith negotiations are preferable to sustained violence.