TERROR was the principal tool of Saddam Hussein's regime.
Within 10 years, the computer had replaced television as the principal tool of political propagandists.
Its principal tool is the Minerals and Petroleum Resources Development Bill, which Parliament will try to complete beginning Tuesday.
The principal tool for assuring reliability of stockpile weapons is surveillance, in which samples are periodically disassembled and examined.
At the dawn of the technological age, shoe leather was the detective's principal tool, but sheer persistence could work wonders.
The ax again became the principal tool on the return to the more primitive state of technology.
New York was one of the first to use the program, and it remains the principal tool to combat street homelessness in most urban areas across the nation.
Property values are used as the principal tool of urban regeneration and, when those values fail to materialise, so does the regeneration.
But there is reason to doubt either the sincerity or analytical rigour of BP's faith in carbon pricing as the principal tool for tackling climate change.
Several of the wounded protesters said the gunmen were the plainclothes enforcers who have served as the government's principal tool against the demonstrations.
In addition, the budget has developed as a principal tool in planning future programs, deciding priorities, managing current programs, linking executive with legislature, and developing control and accountability.
