"Congress finds that the high incidence of crime in the United States threatens the peace, security, and general welfare of the Nation and its citizens. To prevent crime and to insure the greater safety of the people, law' enforcement efforts must be better coordinated, intensified, and made more effective at all levels of government. Congress finds further that crime is essentially a local problem that must be dealt with by State and local governments if it is to be controlled effectively. It is therefore the declared policy of the Congress to assist State and local governments in strengthening and improving law enforcement at every level by national assistance. It is the purpose of this title to (1) encourage States and units of general local government to prepare and adopt comprehensive plans based upon their evaluation of State and local problems of law enforcement; (2) authorize grants to States and units of local government in order to improve and strengthen law enforcement; and (3) encourage research and development directed toward the improvement of law enforcement and the development of new methods for the prevention and reduction of crime and the detection and apprehension of criminals."