It’s becoming increasingly clear that the U.S. prison at Guantanamo Bay, Cuba, isn’t going to be closed during President Obama’s administration — or beyond, despite the administration’s efforts. That raises a deep question about foreign policy and the rule of law: What if Guantanamo never closes, and some of its detainees remain there for the rest of their lives?

The sad truth is that the continued operation of the prison is unlikely to do any more long-term damage to the U.S. reputation abroad — because the world has already come to the conclusion that the U.S. is no better than anyone else when it comes to dealing with terrorists.

But domestically, the continued operation of the prison will do ongoing harm to the coherence and legitimacy of the U.S. legal system.

Start with some hard political truths.

It’s true the U.S. Supreme Court has taken Guantanamo into its jurisdiction, and the worst Al-Qaida detainees are being put on trial. But more than 50 others remain in legal limbo, treated as permanent prisoners of war in a conflict that has no way to end. Their detention calls into question the basic ideas of due process, no matter what legal justification the federal government gives for it.

There’s now a State Department official responsible for finding countries willing to take detainees who’ve been recommended for transfer — and perhaps before the end of Obama’s term he might be able to find homes for some. But most of the 52 detainees who are cleared for release are Yemenis — and there’s essentially zero chance Yemen will be secure enough to take them before Obama’s term ends in January 2017. They would have to be resettled elsewhere.

Then there’s the question of the 54 detainees who haven’t been charged with crimes but have been classified as too dangerous to release. The only way they can be moved off the island is if Congress agrees to a plan the executive branch is supposed to put forward.

But why would a partisan Republican Congress, in the run-up to a presidential election, give the outgoing Democratic president the victory of fulfilling his campaign promise to close the prison? Excuses won’t be hard to find — congressional Republicans can just say they aren’t convinced a domestic military detention facility would be safe enough. To his credit, Sen. John McCain has tried to negotiate a political compromise. But it seems extremely unlikely he’ll be able to persuade House Republicans to give the Democrats such a gift. And it’s unclear what the Obama administration could realistically give them in return.

The costs of Guantanamo to America’s international reputation have been substantial. The abuse at the Abu Ghraib prison in Iraq was in a sense more shameful, because of the public outcry and belief that the techniques used were more obviously a form of torture. But the U.S. was able to respond by disclaiming those techniques and prosecuting at least some of the (low-level) offenders. But Guantanamo represents official government policy, and always has. The prison was — and to an important extent remains — a symbol of U.S. desire and capacity to create a zone of lawlessness. It matters that it’s outside the U.S. And the fact that the Supreme Court held that the Constitution applies there has done little to mitigate the international perception.

Over the course of the last decade, well-meaning judges and lawyers have struggled to incorporate Guantanamo within existing legal frameworks. The Supreme Court deserves credit for saying detainees there were entitled to the protections of habeas corpus. And the prosecutors who are trying Khalid Sheikh Mohammed and his associates for the Sept. 11 attacks are sincerely trying to give them a fair trial before getting them executed.

But these efforts haven’t been enough to tame the effect of Guantanamo on the rule of law in the U.S. The detention hearings at Guantanamo, heavily censored because of classified information, haven’t managed to resemble credible legal proceedings in which people are imprisoned on the basis of compelling evidence. The Sept. 11 trials, too, seem too remote, too militarized and too inevitable in their outcomes to feel like fair criminal proceedings. Far from being closely scrutinized or watched in the U.S., the trials seem weirdly cut off from American reality — in large part because they’re taking place in Guantanamo.

The existence of these unique, strange, outlying legal proceedings affects the broader legal community’s commitment to due process. Fairness demands regularity. Irregularity therefore challenges the ideal of fairness. Most lawyers’ response is to look away in the hopes of not becoming infected. But denial, which can work on the surface, doesn’t successfully suppress the deep knowledge that the U.S. legal system has been sullied.

It’s even worse with respect to the permanent detainees. The U.S. government says it’s within its rights to keep them as prisoners of war in the conflict with Al-Qaida. But the POW rules assume a conflict between international parties that might conceivably be ended by a peace treaty. There will be no such end to the legal conflict between Al-Qaida and the U.S. That means the detainees can be held forever.

This situation emphasizes how unsatisfying it is to rely on wartime detention power, as the administration has done with the Guantanamo inmates. Deep down, the legal system knows the reasoning is doubtful, based as it is on a creative theory of unilateral war. So long as the detention persists — which could be indefinitely — it’ll remain a stain on the rule of law.

If Obama fails to close Guantanamo, it won’t just be a defeat for him. It’s a defeat for law itself.