By Paul Kurtz

PHILADELPHIA (CBS) — On this, the one-month anniversary of the Sandy Hook school massacre in Connecticut, Philadelphia mayor Michael Nutter has announced a code of corporate conduct — to be known as the “Sandy Hook Principles” — for gun and ammunition manufacturers, distributors, and retailers.

The list of 20 principles includes stopping the sale, production, design, and conversion of assault weapons for use by civilians, and conducting background checks for all gun and ammunition sales or transfers.

The mayor is asking all cities, states, and institutions that hold investments with companies involved in the firearms business to adopt the Sandy Hook Principles and make those companies do the same.

“Once a company is notified that its operations are subject to the Sandy Hook Principles, that company must endorse and adhere to the principles within the time determined by the appropriate authority,” the mayor said, “or economic disinvestment actions will commence.”

Later this week, Nutter will introduce a resolution at a meeting of the US Conference of Mayors, of which he is president, to review the principles.   And next week, city solicitor Shelley Smith will ask the city’s pension board to endorse and adopt the principles and begin notifying companies that are subject to them.

If a company rejects the principles, Nutter says, the City of Philadelphia should not support that company with its investments.

The mayor is hoping this idea will sprout into a nationwide movement, much like the Sullivan Principles helped get rid of the apartheid regime in South Africa.   The Sullivan Principles outlined a human rights and equal opportunity code of conduct for companies doing business with South Africa.