President Obama’s decision not to go to Congress for help in establishing reasonable standards for the continued detention of Guantánamo detainees is a failure of leadership in the project of putting American law on a sound basis for a long-term confrontation with terrorism. It is bad for the country, for national security, and for civil liberties. It represents a virtually wholesale adoption of the failed policies of his predecessor — who, with equal obtuseness, refused to root American detention practices in clear law approved by the legislature and similarly failed to learn from repeated Supreme Court rebukes to this unilateral approach. It violates Obama’s much-noted statement this spring that he would “work with Congress to develop an appropriate legal regime so that our efforts are consistent with our values and our Constitution.” And it delegates a profound and difficult policymaking exercise to the judiciary and, ultimately, to a single man on the Supreme Court.

The only point in Obama’s defense is that few political actors have given him reason to think he would have responsible partners if he did the right thing. Human-rights and civil-liberties activists are so keen to avoid legitimizing detention in legislation that they have treated as a victory the president’s decision to adopt the very policy they have spent the past eight years denouncing.

Congress is not looking statesmanlike, either. Republicans have been too busy making political hay out of Obama’s sputtering closure of Guantánamo to act as constructive participants in this important legislative project. Democrats, always afraid of their shadows on national-security issues, have hidden behind civil-liberties platitudes that most do not really believe. Members across the spectrum have acted boldly only when it comes to making sure that no Guantánamo detainees end up in their districts.

But Obama is president, and presidents go to war with the Congress and civil society they have, not the Congress and civil society they wish they had.

There exists perhaps no area of national policy in which Obama entered office with greater opportunity to create a new politics than the law of counterterrorism. Many conservatives understood that President Bush’s executive-power approach had not succeeded in sustaining robust presidential power to confront the enemy. Many liberals, conversely, understood that the left’s dream of a pure law-enforcement model for defeating Al Qaeda was a fantasy. Obama ran on a platform of “change,” and this was an area where constructive change required, first and foremost, presidential leadership.

We may never know what would have happened had Obama been willing to divert some portion of his prestige from health-care to the creation of a political coalition for strong counterterrorism measures rooted in statutory powers debated and passed by the people’s representatives.

How very curious, though, that so much of American political culture finds it more comfortable for him to get in touch with his inner Dick Cheney than to try.

Benjamin Wittes is a senior fellow at the Brookings Institution. A version of this commentary originally appeared in the Washington Post on Tuesday.