Union County has backed off a plan to let a Princeton University computer scientist examine voting machines where errors occurred in the presidential primary tallies, after the manufacturer of the machines threatened to sue, officials said today.

A Sequoia executive, Edwin Smith, put Union County Clerk Joanne Rajoppi on notice that an independent analysis would violate the licensing agreement between his firm and the county. In a terse two-page letter Smith also argued the voting machine software is a Sequoia trade secret and cannot be handed over to any third party. Last week Rajoppi persuaded the statewide clerk's association to have an independent study of the machines done by Edward Felten, a professor of computer science and public affairs at Princeton University. The Constitutional Officers Association of New Jersey called for the independent review to ensure the integrity of the election process.

Sequoia maintains the errors, which were documented in at least five counties, occurred due to mistakes by poll workers. The firm, which is based in Colorado, examined machines in Middlesex Count, and concluded that poll workers had pushed the wrong buttons on the control panels, resulting in errors in the numbers of ballots cast.

But officials found it odd that such an error never occurred before and the clerk's association wanted further testing.

On the advice of county's attorneys, however, Rajoppi said today she must forego all plans for independent analysis.

That upset Penny Venetis, a Rutgers University law professor representing a group of activists trying to have electronic voting machines scrapped.

"We shouldn't have a corporation dictating how elections are run in the state," Venetis said. "If an elected official believes there was an anomaly and the matter has to be investigated, then the official should be able to consult with computer experts without interference."

The Union County clerk said she intends to write to the state Attorney General's Office again in hopes of convincing the state to call for an independent study. The attorney general oversees the election process.

Read the full story in Tuesday's Star-Ledger.