Can terrorism be eliminated?

Terrorism is commonly seen as a scourge of our times. Can it possibly be eliminated, or are we destined to see increasingly more terrorist violence committed in the future? There are many causes of terrorism, but can violent acts ever be justified? Is one man's terrorist another man's freedom fighter? Optimists point to the IRA and ETA as examples of terrorist groups whose impact has waned. Can we negotiate with other terrorist groups, or is it a forlorn hope to think that we can engage in dialogue with groups such as Al Qaeda or Isis? Should we be shocked by the robust response of the USA, Israel and other countries directly affected by terrorism, or is it time to take firmer military action aimed at defeating those who wish us ill?