Hostage, a person held in captivity to assure that an agreement is observed or to coerce another party into taking (or not taking) some action. Countries in ancient and medieval times sometimes exchanged hostages, often persons of high rank, who could be put to death if certain agreements were broken. Invading armies often take hostages of local citizens to discourage resistance to their occupation. Terrorists sometimes seize hostages both to force concessions from governments and to gain publicity for their cause.
There's no doubt the Boston bombings rattled the U.S. Should the country's policy makers be equally rattled by daily gun violence?
The word "justice" appears in many of the United States' most important documents, including the Declaration of Independence and the Constitution. But for a word that's used so often, its precise definition is still a topic of debate.