US President George W Bush has refused to rule out pardoning former White House aide Lewis "Scooter" Libby, convicted over a CIA-leak case.
Libby was found guilty of perjury in March
Mr Bush commuted Libby's 30-month jail sentence on Monday, drawing criticism from political opponents.
House Speaker Nancy Pelosi said the move showed Mr Bush condoned criminal conduct, and Hillary Clinton said he elevated cronyism over the rule of law.
Libby must still serve a two-year probation and pay a $250,000 fine.
On Tuesday Mr Bush declined to rule out a complete pardon for Libby at a later time.
"As to the future I rule nothing in and nothing out," he told journalists in Washington. But he also reiterated that he thought Libby's non-prison punishments should stand.
Mr Bush described what he said was a "very difficult decision."
He reiterated that Libby's punishment was "severe" and said he took into consideration Libby's background and service to his country.
Republicans, who had called for a full pardon for Libby, welcomed the decision to commute the sentence.
'Betrayal of trust'
The BBC's James Westhead in Washington said the president's decision was a compromise between pardoning Libby outright and allowing his sentence to stand.
WHAT IS CIA LEAK CASE ABOUT?
Libby was found guilty of lying to the FBI and a grand jury over revelations about CIA agent Valerie Plame's identity
Critics said the White House leaked Ms Plame's identity to undermine her husband, ex-ambassador Joseph Wilson
He had publicly cast doubt on the Bush administration's case for war in Iraq
The alleged cover-up, rather than the leak itself, was the subject of the Libby trial
But Ms Pelosi described Mr Bush's intervention as a "betrayal of trust of the American people".
Ms Clinton, a frontrunner in the Democratic race for the presidency, said she was incensed by the move.
"What we saw today was elevating cronyism over the rule of law. And what we saw today was further evidence that this administration has no regard whatsoever for what needs to be held sacred," she told the BBC.
But Republican presidential hopefuls Rudolph Giuliani and Mitt Romney welcomed the decision.
"I believe that the circumstances of this case, where the prosecutor knew that there had not been a crime committed, created a setting where a decision of this nature was reasonable," the New York Times quoted Mr Romney as saying on the campaign trial in Iowa.
Both men said in a Republican presidential debate last month that they would consider a pardon.
Lewis Libby, also known by his nickname, "Scooter" Libby, was found guilty in March of perjury and obstructing justice in a case connected to Washington's decision to invade Iraq.
His trial stemmed from the accusation that the White House had illegally made public the identity of a serving CIA agent, Valerie Plame, in an apparent effort to embarrass her husband.
Ms Plame's husband, a former US diplomat, had publicly criticised the basis for the invasion of Iraq.
Libby was found to have lied to investigators about conversations where he mentioned Ms Plame but he was not convicted of having directly leaked her name.
He was sentenced to two-and-a-half years in prison, two years of probation and a fine of $250,000 (£125,000).
President Bush said he had until now refrained from intervening in the case, waiting instead for the appeals process to take its course.
"I respect the jury's verdict," he said. "But I have concluded that the prison sentence given to Mr Libby is excessive," Mr Bush said.
However, he said, Libby's remaining punishments - the probation period and fine - were "harsh" and would leave his reputation "forever damaged".