Former White House aide Lewis Libby has pleaded not guilty to charges related to the leak of a CIA agent's identity.
Lewis Libby has said he expects to be exonerated
Mr Libby, who was chief of staff to Vice-President Dick Cheney, faces five counts of perjury, making false statements and obstructing justice.
He was one of the most powerful men in the US until he resigned last week. The charges arise from an inquiry into the leak of Valerie Plame's identity.
Her husband - a former ambassador - had criticised the case for invading Iraq.
The inquiry, which is continuing, also investigated the actions of the president's chief political aide, Karl Rove, who has not been charged.
Walking on crutches because of a broken foot, Mr Libby appeared before US District Judge Reggie Walton in Washington DC for the 10-minute court hearing.
After being read the charges and asked for his plea, he said: "With respect, your honour, I plead not guilty."
The judge ordered a new status hearing on 3 February - but did not set a trial date.
Mr Libby faces up to 30 years in prison if convicted but it is widely believed that, if jailed, Mr Libby would be pardoned by President George W Bush when he leaves office.
The former aide has bolstered his legal team by hiring two well-known criminal defence lawyers.
Outside the courthouse, one of them, Ted Wells, said Mr Libby wanted to fight the charges in court, not in the media.
"In pleading not guilty he has declared to the world that he is innocent," Mr Wells said.
"He has declared that he intends to fight the charges in the indictment and he has declared that he wants to clear his good name, and he wants a jury trial."
If the case does go to trial, the White House will have to brace itself for more political damage, says the BBC's Oliver Conway in Washington.
Patrick Fitzgerald says his inquiry into the leak is not yet over
Mr Cheney and other top Bush administration officials could be summoned to testify.
Ms Plame's name was exposed by conservative columnist Robert Novak after her husband, Joseph Wilson, accused the Bush administration of distorting intelligence in the run-up to the Iraq war to exaggerate the threat from Saddam Hussein's regime.
Mr Wilson accused the Bush administration of covering up the results of his inquiry into whether Iraq was trying to obtain uranium from Niger.
Mr Bush included the Niger allegation in his State of the Union speech in which he accused Iraq of building weapons of mass destruction.