[9] A 1950 study by the NCPC found that the small Southwest quarter of the city suffered from high concentrations of old and poorly maintained buildings, overcrowding, and threats to public health (such as lack of running indoor water, sewage systems, electricity, central heating, and indoor toilets).

[7][10] Competing visions for the redevelopment ranged from renovation to wholesale leveling of neighborhoods, but the latter view prevailed as more likely to qualify for federal funding.

[11] Original plans called for the demolition of almost all structures in Southwest Washington beginning in 1950, but legal challenges led to piecemeal razing of the area until the mid-1950s.

[12][13] The United States Department of Health, Education and Welfare wished to purchase the site for its new headquarters, but the RLA declined to sell the property.

[12] The building was constructed under an agreement between the General Services Administration (GSA) and Boston developer David Nassif, Sr.

[14] GSA (the property owner and manager for the U.S. federal government) began seeking to lease or build a structure to house the new agency in late 1965.

[1] The main entrance faced 7th Street SW.[18] It included a central courtyard (open to the sky) featuring a fountain, footpaths, benches, and landscaping.

[16] When the pension fund refused to provide the loan, Riggs Bank sued for payment and threatened to foreclose on the Nassif Building.

[24] Over the years, so many government workers complained of ailments while working in the structure that some believed it suffered from sick building syndrome.

[1] However, when the Department of Transportation announced it would leave the building in 2000,[25] the owners promised a $100 million renovation that included a new air ventilation and cleaning system as an inducement for the agency to stay.

[1] The owners also unsuccessfully sued the General Services Administration in 1999 to force it to renew the federal lease on the building.

[1][3][30] The security enhancements made the office building suitable for all federal agencies except for the United States Department of Defense.

The celebrated key visual feature of the building,[23] its exterior vertical white marble ribbing, was completely removed after it was found to be bowed from age and weather.

[33] Other energy-saving enhancements included motion and daylight detectors to turn lights off when not needed,[1] and special exterior windows that automatically dim to prevent daytime heating.

[3] The park, which is now no longer accessible by the public, also includes a huge granite abstract art sculpture ("Legacy") by Richard Deutsch.

[35] The renovation installed artwork by internationally-known artist Stephen Knapp near this entrance, in which strong beams of light are passed through dyed glass to splay brightly colored patterns on the ceiling.

[2] In August 2010, the United States Securities and Exchange Commission (SEC) signed a letter contract for 900,000 square feet (84,000 m2) of space at Constitution Center.

[43] SEC chairman Mary Schapiro was strongly criticized by Republicans in the United States House of Representatives for her handling of the lease, which she had personally approved.

[44] In early July 2011, Nassif Associates said it had agreed to release the SEC from occupying 550,000 square feet (51,000 m2) of space at Constitution Center.

The company asked the SEC to reimburse it for $45 million in build-out and other expenses incurred between August 2010 and July 2011, but the agency declined to do so.

[45][46] At the same time, the United States Department of Justice said it was considering whether to prosecute officials at the SEC over the lease's handling and the alleged forging of documents designed to justify it.

In October 2011, the United States House Committee on Transportation and Infrastructure voted 31-to-22 to permit the Federal Trade Commission to lease 160,000 square feet (15,000 m2) of space at Constitution Center and vacate the Apex Building (which would be turned over to the National Gallery of Art).

[48] Although Congress did not adopt this legislation, the Transportation and Infrastructure Committee in March 2012 directed the General Services Administration (GSA) to analyze space needs for the Federal Trade Commission and several other federal agencies in the District of Columbia and issue a report to the committee on how Constitution Center could meet these needs.

[4] GSA reported in June 2012 that the Constitution Center held too little space to house the entire FTC, and it was too costly to do so (after accounting for moving expenses and rental prices).

[42] In late May, the Federal Aviation Administration said it might lease 270,000 square feet (25,000 m2) of space in the building as part of a major consolidation of six of its offices in the city.

[52] On April 22, 2011, David Nassif Associates announced it was putting Constitution Center up for sale and said it hoped to find a buyer by the end of summer 2011.

)[56] When the deal closed in February 2013, David Nassif Associates announced it would wind down its operations and liquidate its remaining obligations.