Research In Motion says its BlackBerry e-mail device is such a vital part of the “critical infrastructure” in America, including Wall Street, that a court shouldn’t shut down the service.

The argument, included in court papers filed yesterday, is one of several the Waterloo, Canada-based company is making to persuade a judge not to issue an order that would shut down American BlackBerry service. An appeals court last year upheld a finding that the service infringed patents owned by NTP Incorporated.

Research In Motion said the BlackBerry is key to American “economic security” and part of the nation’s emergency and disaster planning. A shutdown would interrupt service to about 2 million customers in America, including Wall Street traders and corporate executives. Government officials would be exempt.

“I like RIM’s argument that the country depends on commerce and depends on people being able to use these devices,” a patent lawyer at Powell Goldstein in Atlanta, Scott Creasman, said. The judge should look at “the harm to the public versus any harm to NTP, which is strictly monetary.”

U.S. District Judge James Spencer in Richmond, Virginia, who presided over the November 2002 patent trial that Research In Motion lost, hasn’t scheduled hearings on whether to shut down the BlackBerry service or how much Research In Motion should pay. The filings yesterday by Research In Motion and NTP are the first arguments on the issues.

“It would be extraordinarily impractical, if not impossible, to devise and administer an injunction that would protect government and private sector BlackBerry users who would be, or should be, excluded from an injunction,” Research In Motion said.

NTP, a closely held patent-licensing firm based in Arlington, Virginia, said Research In Motion overstates the difficulty of shutting off service to only some users.

“RIM must simply turn those accounts off in the same fashion as when a customer fails to pay its bill,” NTP said. It has offered to give a 30-day transition period.

Research In Motion said a possible “workaround” it would implement if an injunction is issued would “create unnecessary concerns” and “burden” users by requiring the reloading of software onto servers and Blackberry devices.

NTP said the court shouldn’t be swayed by possible disruptions to private sector BlackBerry customers who have known about the case for more than two years.

In its filing, Research In Motion included statements from a former Department of Homeland Security official who said the BlackBerry worked after Hurricane Katrina struck the Gulf Coast when cell phones didn’t, and the head of a New England health group who says the BlackBerry is part of its plan for a response to an avian flu outbreak.