All five living presidents gathered in Texas Thursday for a feel-good moment at the opening of the George W. Bush Presidential Library and Museum, which is supposed to symbolize the legacy that Mr. Bush has been trying to polish. President Obama called it a “special day for our democracy.” Mr. Bush spoke about having made “the tough decisions” to protect America. They all had a nice chuckle when President Bill Clinton joked about former presidents using their libraries to rewrite history.

But there is another building, far from Dallas on land leased from Cuba, that symbolizes Mr. Bush’s legacy in a darker, truer way: the military penal complex at Guantánamo Bay where Mr. Bush imprisoned hundreds of men after the Sept. 11, 2001, attacks, a vast majority guilty of no crime.

It became the embodiment of his dangerous expansion of executive power and the lawless detentions, secret prisons and torture that went along with them. It is now also a reminder of Mr. Obama’s failure to close the prison as he promised when he took office, and of the malicious interference by Congress in any effort to justly try and punish the Guantánamo inmates.

There are still 166 men there — virtually all of them held without charges, some for more than a decade. More than half have been cleared for release but are still imprisoned because of a law that requires individual Pentagon waivers. The administration eliminated the State Department post charged with working with other countries to transfer the prisoners so those waivers might be issued.