TRENTON, N.J. --- In New Jersey, the governor's e-mails might shed light on whether he inappropriately conferred with a labor leader he once dated. In Detroit, the mayor's text messages revealed a sexually charged scandal. In California, a fight rages for access to e-mails sent by a city councilwoman about a controversial biological laboratory.

Even the White House has been under pressure from Democrats in Congress over its problem-plagued e-mail system.

While e-mail and text messaging has become a popular way to communicate, governments at all levels are often unwilling to let the public see the e-mails of their elected officials.

Officially, e-mails in all but a handful of states are treated like paper documents and subject to Freedom of Information requests. But most of these states have rules allowing them to choose which e-mails to turn over, and most decide on their own when e-mail records are deleted.

"There seems to be an attitude throughout government -- at all levels -- that somehow electronic communications are of its own kind and not subject to the laws in the way that print communications are," said Patrice McDermott, the director of OpenTheGovernment.org.

"So we keep hearing reports of governors and mayors who decree that their e-mail records can be destroyed, in six weeks or six months, with no appraisal for permanent value and no review by an independent body," she said.

Open records advocates contend that by keeping electronic communications private, states are giving their elected officials an avenue to operate in secret -- they use taxpayer-funded computers to send and receive e-mail but with little or no obligation to make such communications public.

New Jersey Gov. Jon S. Corzine is fighting in court to keep secret his e-mails with ex-girlfriend Carla Katz, the leader of a union representing thousands of state workers. State Republicans sued when Mr. Corzine refused to turn over his e-mails.

"He seems to think he's still running a private company where he gets to set the rules and ignore them when it serves his purpose," said Tom Wilson, the New Jersey Republican Party chief.

Mr. Corzine says he's protecting privileges afforded governors to keep communication private while also shielding his personal life from public examination.

Mr. Corzine is among several governors who say they don't use e-mail. Without a system that grants access to e-mails, open records advocates wonder how the public would know whether that's true.

Denial to requests for e-mail access seems to be common.

The Detroit Free Press sought access to text messages sent between Detroit Mayor Kwame Kilpatrick and his chief of staff, Christine Beatty. The Free Press was unable to get access through a records request, but it still got about 14,000 text messages on Ms. Beatty's city-issued pager through another source it hasn't named.

Those messages unleashed a sexually charged scandal that has brought calls for Mr. Kilpatrick's resignation.

The mayor's office contends the text messages don't fall under public information requirements because they were not transmitted on city-owned equipment.

When governments do release e-mails -- voluntarily or not -- these documents can prove revealing to the public. For example:

- In 2005, several media outlets, including the AP, sought e-mails from the office of Jim Black, then the House speaker in North Carolina, about possible lobbying work performed by his political director, who was also working for a lottery company seeking to do business for the state.

Mr. Black eventually released documents sought by a federal grand jury and 300 additional pages of e-mails, some of which showed his political director was lobbying the speaker even though she wasn't registered to lobby.

- E-mails obtained by AP in Iowa showed how the staff of Gov. Chet Culver formulated a public statement after August's bridge collapse in neighboring Minnesota. The e-mails show a staff eager to assure residents of their safety, but at odds over what kind of guarantees the governor could offer that bridges were safe. "The big question at this stage is whether or not a public official can avoid the requirements of the law by simply going home at night and using a personal computer," said Tom Newton, the general counsel for the California Newspaper Publishers Association.

That's the issue in San Francisco, where messages to Mayor Gavin Newsom about a fuel spill were sent to and from his personal iPhone, said Newsom spokesman Nathan Ballard, and were sought by a resident not affiliated with the news media.

"We're not going to start handing over the personal messages of someone just because they work for the city," Mr. Ballard said.

The messages were between Mr. Newsom and his chief of staff and involved the city's spill response, Mr. Ballard said.

On Capitol Hill and in federal court, a congressional committee and two private groups are pushing for information on how the White House has handled its e-mail for the past six years.

Ms. McDermott, of OpenTheGovernment.org, said federal policy calls for treating all e-mail the same, regardless of the level of office, and printing it out before destroying the electronic version. "This would be bad enough, but it is very uncertain that all record mail is even being printed," she said. "Most federal agencies do not have an electronic record-management for their electronic records and this is especially a problem for e-mail records because of the enormous volume."