TOMORROW, Egyptian President Hosni Mubarak will pardon hundreds of prisoners who have served more than half of their sentences, an annual gesture of mercy coinciding with commemorations of the July 23, 1952, "revolution" that brought Egypt's military-backed regime to power. If past practice holds, those freed will include some convicted of violent crimes such as murder and rape. Yet the government has announced that people convicted of the distinctly non-heinous crime of forgery will not be eligible. Is Egypt suffering from an intolerable plague of counterfeiters? No, but its best-known political prisoner, Ayman Nour, happened to be convicted on that charge in a blatantly rigged 2006 trial.

Mr. Nour is a liberal democrat who, inspired in part by President Bush's call for democracy in Egypt, challenged Mr. Mubarak's reelection as president in 2005. His reward was to be sentenced to five years in prison, where he has been subjected to beatings and other abuse. Mr. Mubarak's relentless and vindictive persecution of Mr. Nour can only be seen as a calculated and personal insult to Mr. Bush and his "freedom agenda."

Mr. Nour has now served more than half of his five-year sentence. He is in poor health, suffering from diabetes and heart problems that have led to repeated hospitalization. He became eligible for parole in the spring; he has also appealed for release on medical grounds. Yet it seems likely that he will be forced to serve his full term, keeping him in prison for two years after Mr. Bush leaves the White House.

The president has made token gestures toward fulfilling his second inaugural promise to defend dissidents such as Mr. Nour. A year ago he mentioned his case in a speech in Prague; in May he told reporters that he had brought up Mr. Nour during a meeting he had with Mr. Mubarak. But the administration has shrunk from the measures it once was willing to take to help Egyptian political prisoners. For example, Mr. Bush withheld millions in U.S. aid to Egypt to win the freedom of dissident intellectual Saad Eddin Ibrahim in 2002.

In the past two years, Mr. Bush has all but abandoned his freedom agenda, allowing the State Department to return to the appeasement of autocrats such as Mr. Mubarak. We'd think, though, that the president would not be content to ignore such blatant mistreatment of someone who believed his words. The leverage to respond to Mr. Mubarak's behavior -- in the form of excessive and wasteful U.S. aid to the Egyptian military -- is readily available. If Mr. Nour is not freed this week, Mr. Bush ought to feel morally obligated to use that leverage.