BERKELEY (KCBS) – Consumer advocate Ralph Nader is trying to use his influence to persuade the U.S. Postal Service to not close Berkeley’s Main Post Office.

About 200 people gathered at the Berkeley Main Post Office on Tuesday. Nader said it’s important to prevent the USPS from shutting a building that is on the National Register of Historic Places.

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“This is not just a matter of stamps or delivery on Saturday, as important as that is,” he told the crowd. “This is a fundamental institution that binds the country together.”

But U.S. Postal Service spokesman Gus Ruiz said the building has outlived its usefulness.

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“We’re looking at a building where no carriers are housed anymore, and the only thing we need is a retail front,” Ruiz said. “That takes about 4,000 square feet and that building is close to 57,000 square feet.”

The U.S. Postal Service announced in 2012 that it planned to sell the building in Downtown Berkeley, which has been met with a great deal of opposition.

The USPS has argued that it is trying to reduce a multi-billion dollar deficit, and has several interested buyers.

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But Nader called that “an exaggerated crisis.”