Eminent Domain

Eminent Domain is a government action by which private land can be purchased (or in some cases, taken) with or without compensation by the government for its use. The idea of Eminent Domain is present in the United States Constitution through final clause of the Fifth Amendment:
No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time of War or public danger; nor shall any person be subject for the same offense to be twice put in jeopardy of life or limb; nor shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without due process of law; nor shall private property be taken for public use, without just compensation.


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Speech Relevance

From 'A Time For Choosing':
Meanwhile, back in the city, under urban renewal the assault on freedom carries on. Private property rights are so diluted that public interest is almost anything that a few government planners decide it should be. In a program that takes for the needy and gives to the greedy, we see such spectacles as in Cleveland, Ohio, a million-and-a-half-dollar building completed only three years ago must be destroyed to make way for what government officials call a "more compatible use of the land."
I believe Reagan's point regards Eminent Domain, which has be stretched to the point where taking property from one private entity to give to another private entity capable of paying greater taxes to the government is a "public use".

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Source Links

Fifth Amendment to the US Constitution (Wikipedia)