Civilians aren't expected to understand Temple University physics professor Xiaoxing Xi's research on thin-film superconductivity. The trouble is that the federal authorities who had him arrested don't seem to have understood it either.

Early one morning a few months ago, a dozen or so armed FBI agents searched Xi's Penn Valley home and took him away in handcuffs in front of his wife and daughters. Last week, however, they moved to drop charges that the professor had shared sensitive technological information with Chinese scientists.

An American citizen who has lived in the United States since 1989, Xi lost his chairmanship of Temple's physics department as a result of a four-count wire-fraud indictment that, his successor told The Inquirer this week, "came close to destroying his life." In their motion to dismiss the case late Friday, authorities explained wanly that "new information came to the attention of the government." Specifically, according to Xi's attorney, a number of persuasive independent experts rounded up in the wake of the charges confirmed the professor's assertion that the blueprints he shared with Chinese contacts did not depict the equipment prosecutors claimed it did.

It's disturbing enough that U.S. Attorney Zane Memeger's office may not have sufficiently consulted such experts before going ahead with serious criminal charges. Worse, amid an apparently overzealous effort to combat Chinese spying, Xi's is the second such high-profile case of prosecutorial overextension in less than a year. In March, federal prosecutors in Ohio dropped their case against another Chinese American scientist, National Weather Service hydrologist Sherry Chen, who had been accused of sharing sensitive government information with Chinese officials.

If the case against Xi was botched as badly as it appears to have been, the U.S. Attorney's Office can begin to undo the damage and clear his name with a full-throated acknowledgment of its errors. Merely mumbling the bureaucratic equivalent of "Never mind" won't do.

Meanwhile, the Obama administration and the Justice Department should consider whether their declared war on a legitimate threat, China's avid espionage, is inflicting too much collateral damage among innocent Chinese Americans. Our history is already littered with enough examples of immigrants unfairly targeted for collaboration with their countries of origin that turns out to be more imagined than real.