The term "wiretapping" may seem somewhat quaint in this age of wireless Internet. But wiretaps, defined as intercepted communications, are a major concern in New York white collar crime cases.

The danger of government over-reaching in cases involving charges of fraud, money laundering, embezzlement or insider trading is very real. People's privacy - and constitutional rights - are increasingly at risk.

The trend in recent years has been for Congress to keep adding to the list of suspected crimes for which the law permits wiretaps under certain conditions. Even with those additions, however, the government's attempt to use intercepted cellphone conversations as evidence in securities fraud investigations is questionable.

Yet that is what seems to be happening in the charges being brought against Rajat Gupta. Federal prosecutors have accused Gupta, a former director of Goldman Sachs, of passing insider information along to Galleon Group hedge fund manager Raj Rajaratnam.

Last month, Rajaratnam reported to federal prison to begin serving an 11-year sentence - the longest ever for insider trading.

Gupta's defense lawyers argue that the use of evidence gained from intercepted mobile phone conversations is not permitted in investigations of suspected insider trading.

It's worth taking a moment to remind ourselves why the law has historically restricted the government's ability to eavesdrop on private conversations. The rationale for the restrictions is based on respect for individual privacy - and on the constitutional right to be protected from unreasonable searches.

These restrictions have been loosened in recent years. But that doesn't mean they are gone entirely, especially in investigations where there is no credible claim that national security is stake.

Source: "U.S. Defends Use of Wiretap Evidence in Rajat Gupta Prosecution," Businessweek, 1-20-12