WASHINGTON (Reuters) - Free speech, a key tenet of the U.S. Constitution, is facing unusual challenges in pre-war, post 9/11 America -- where wearing an anti-war T-shirt prompted an arrest and lampooning the vice president's wife drew a letter from a White House lawyer.

The creator of a satirical Web site that took aim at Lynne Cheney, wife of Vice President Dick Cheney, said he felt a chill when the letter on White House stationery arrived.

"I read it very carefully and while I could see that technically it was a request ... the overall tone of it and the citing of various and sundry cases was obviously threatening in nature," John Wooden said by telephone from Brooklyn, New York. "You don't get just a request from the vice president's office."

The letter from David Addington, a counsel to the vice president, asked Wooden to remove pictures and a "fictitious biography" of Mrs. Cheney from the site, www.whitehouse.org.

Instead, Wooden added red clown noses to pictures of Mrs. Cheney, over the word "CENSORED," and posted Addington's letter. A Cheney aide who asked not to be identified said neither the vice president nor Mrs. Cheney were aware of the letter before it was sent and consider the matter closed.

The New York Civil Liberties Union has taken up the case and is waiting for a reply from the White House, since it considers this matter typical of an atmosphere of repression in the United States.

"It's clear that the Bush-Cheney administration has put the blocks in place for a repressive climate on even the most fundamental and obvious of issues, like the right to have a Web site that satirizes the vice president's wife," said Donna Lieberman, the group's executive director.

Lieberman said another sign of the times was the arrest earlier this week of a lawyer at a public mall near Albany, New York. The lawyer was charged with trespassing after refusing to take off a "Give Peace A Chance" T-shirt he had just bought at the mall.

The New York group's parent, the American Civil Liberties Union, has reported a 15 percent surge in membership since the Sept. 11, 2001, hijack attacks on the World Trade Center and the Pentagon.

Civil libertarians raised concerns soon after the attacks that the wish to find the guilty might result in violation of individual rights. They continue to chafe at the USA Patriot Act, passed 45 days after the attacks, which gave the government greater powers to eavesdrop and detain immigrants.

TAKING AIM AT PATRIOT ACT

The ACLU launched a campaign against new legislation being drafted by the Justice Department that would create a terrorist identification database and limit the disclosure of certain information and allow pretrial detention of suspected terrorists without bail.

In full-page advertisements in The New York Times and The Washington Times, the ACLU said the Patriot Act makes it legal "for government agents to break into your home when you are away, conduct a search -- and keep you from finding out for days, weeks or even months that a warrant was ever issued?"

The ad said the new legislation, dubbed Patriot II, would give the government "even broader authority to search our homes, learn what we read, find out where we vacation and monitor what drugs our doctors prescribe."

Justice Department officials confirmed that the new legislation was being drafted in February, but Attorney General John Ashcroft said at a congressional hearing this week that the legislation had not been finalized.

Constitutional law expert Neal Katyal of Georgetown University said the Patriot Act and its possible sequel are not in and of themselves dangers to individual U.S. rights, but said various moves by the Bush administration since 9/11 add up to "a dramatic attack on civil liberties in this country."