[TheRealVille]

Why do you think that the 10 Commandments is plastered all over the Supreme Court building, not only on the outside of the building, but all over the inside of the judges chambers and in various places throughout the entire building, that I described of earlier?

As stated in the post above, it is a depiction of Moses as a lawgiver, and the commandments as merely a depiction of law. Confucius and Solon are also there.

Where do Moses and the 10 Commandments appear in the Supreme Court building?

Research by Jim Allision. Writing by Tom Peters.
This document will look at the three topics: (1) unquestioned representations of Moses and/or the 10 Commandments, (2) a questionable representation of the 10 Commandments, and (3) important architecture in which Moses and the 10 Commandments are omitted.
Unquestioned representations of Moses and/or the 10 Commandments:

Moses and/or the 10 Commandments appear three times in the architectural embellishment of the Supreme Court building. Two of these representations depict Moses as simply one of several important lawgivers; these representations tend to disprove the idea that the 10 Commandments have some special relationship to American law. The third instance has the Commandments as one of two artistic adornments on a set of doors.
Justice the Guardian of Liberty. This sculpture is a frieze located above the East (back) entrance to the Supreme Court building. Moses (holding blank tablets) is depicted as one of trio of three Eastern law givers (Confucius, Solon, and Moses). The trio is surrounded by a variety of allegorical figures representing legal themes. The artist, Herman MacNeil, described his intentions in creating the sculpture as follows:

Law as an element of civilization was normally and naturally derived or inherited in this country from former civilizations. The "Eastern Pediment" of the Supreme Court Building suggests therefore the treatment of such fundamental laws and precepts as are derived from the East. Moses, Confucius and Solon are chosen as representing three great civilizations and form the central group of this Pediment (Descriptions of the Friezes in the Courtroom of the Supreme Court of the United States and of the East and West Pediments of the Building Exterior, p. 9).
Nothing in MacNeil's description, in other words, suggests any special connection between American law and the 10 Commandments. Moses is simply one of three important lawgivers from the East.

The South Courtroom Frieze. The Courtroom friezes were designed by sculptor Adolph Weinman. These friezes are located well above the courtroom bench, on all four walls. The South and North wall friezes form a group that depicts a procession of 18 important lawgivers: Menes, Hammurabi, Moses, Solomon, Lycurgus, Solon, Draco, Confucius, Augustus, Justinian, Mohammed, Charlemagne, King John, St. Louis, Hugo Grotius, William Blackstone, John Marshall, and Napoleon. Moses is holding blank tablets. The Moses figure is no larger or more important than any other lawgiver. Again, there is nothing here to suggest and special connection between the 10 Commandments and American law.

The Curator's office makes the following comments on Weinman's North and South frieze sculptures:

Weinman's training emphasized a correlation between the sculptural subject and the function of the building and, because of this, Gilbert relied on him to choose the subjects and figures that best reflected the function of the Supreme Court building. Faithful to classical sources, Weinman designed for the Courtroom friezes a procession of "great lawgivers of history," from many civilizations, to portray the development of secular law (p. 2, emphasis ours).
The Oak Courtroom Doors. The oak doors separating the courtroom from the central hallway of the Supreme Court building contain a representation of tablets bearing the Roman numerals one through ten; the Commandments themselves are not written out. The tablets depiction is located on the inside bottom of the doors. A second artistic embellishment (a circle with engraved woodwork) is located at eye-level on the inside of the doors. Click here for a close-up of the tablet depiction. Click here for a picture of the entire door (the tablet depiction is the bottom circle).

It's interesting to note that the engraved circle embellishment is placed at eye level, while the 10 Commandment depiction is placed toward the bottom of the door in an out-of-the-way position. The Commandments are, of course, a perfectly logical artistic embellishment for a court of law but, given its placement, it doesn't appear that the artist has any special regard for the Commandments. Additionally, we note that the oak doors seem to be of little consequence as artistic creations. A search of the University of Louisville library turned up a number of books that discuss the architecture of the Supreme Court, and while all of them discuss the two pieces mentioned above, none of them mention the doors. It does not appear, in other words, that the doors are regarded very highly by scholars of art.

http://candst.tripod.com/tnppage/arg8a.htm