Americans won’t close a terror prison when the terror threat is rising.

The day after he was first sworn in, President Obama issued an executive order declaring that he would shut down the terrorist detention camp at Guantanamo Bay in Cuba “no later than 1 year from the date of this order.” That was January 2009 in one of his first acts as President. Congress has since used its power of the purse to frustrate the President’s effort. So on Tuesday he said he’s going to try again in one of his last acts as President. It’s not going to happen—at least not if Mr. Obama follows the law. Polls show the American people oppose closing Gitmo by about two to one, politicians in both parties oppose closing it, and the past seven years have taught that the camp plays an important role in keeping America safe. One reason is because Americans have figured out that the alternative is bringing these terrorists to the mainland. It’s easy to call for Gitmo’s closure in the abstract. It’s harder to explain to voters why Khalid Sheikh Mohammed and other killers may soon move into a prison near you. No doubt this explains why the Pentagon plan submitted to Congress on Tuesday is so vague on details—especially the names of the “appropriate site[s] in the continental United States” where the detainees would be sent. One likely destination would be the supermax prison in Florence, Colorado, which explains why Democratic Senator Michael Bennet rejects Mr. Obama’s plan. House Speaker Paul Ryan said Tuesday the proposal is dead on arrival in the GOP Congress, but a Democratic Congress first put the kibosh on the transfer. In 2009, when Mr. Obama was still riding high, Congress responded to his executive order by passing language forbidding the use of government funds to transfer Gitmo detainees. The vote in the Democratic Senate that May was 90 to 6 against Mr. Obama. Similar language has since passed several times with strong bipartisan support, most recently in November as part of the National Defense Authorization Act. Mr. Obama issued a signing statement saying he opposed the Gitmo language, but he signed the bill. In the liberal caricature, Guantanamo was set up by former Vice President Dick Cheney to shred the Constitution. In reality it filled a void by providing a secure location where we can hold enemy combatants who have violated the laws of war, who may not be prosecutable in a civilian court, and who are too dangerous to release.

Guantanamo also provides an opportunity to interrogate terrorists over an extended period of time. In part because Mr. Obama has refused to add to the Gitmo population, his Administration has focused on killing terrorists from afar with drones rather than capturing them. Sometimes terrorists must be killed with drones, but more captives could yield invaluable intelligence to prevent future attacks. We know this because so many detainees released by the Bush and Obama Administrations have returned to the battlefield. The Director of National Intelligence says that of the 653 detainees transferred out of Gitmo through July 2015, 117 are confirmed to have re-engaged as terrorists and another 79 are suspected of re-engaging. Most of the remaining 91 are the worst of the worst, and 46 aren’t even recommended for transfer.

This potential risk to American security is why former Defense Secretary Chuck Hagel resisted Mr. Obama’s closure plans. Mr. Hagel has said he believes this is the main reason Mr. Obama fired him. It’s possible that Mr. Obama’s Tuesday plan is merely one more political set-up, that what he really intends is to issue another executive order closing Guantanamo if Congress won’t go along with his proposals.

The great political irony is that Mr. Obama is the main cause of his own Guantanamo failure. If he hadn’t let Islamic State rise in Syria and Iraq, if he hadn’t let Libya become another terror incubator, and if he hadn’t let al Qaeda make a comeback via multiple local franchises, the American people might feel more relaxed about closing the terror prison. As the tide of war keeps rising, Americans know they need it.

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