For weeks, Republicans in Congress have been saying what Democrats are finally beginning to acknowledge: that the administration has no plan for closing Guantanamo, and that closing this secure facility without a safe alternative is irresponsible, dangerous, and unacceptable.

Over the years, Guantanamo has housed some of the most hardened terrorists ever captured alive, and many of those who remain are the worst of the worst. Some have already killed innocent Americans, and many are outspoken about their desire to kill more.

These men are exactly where they belong: locked up in a safe and secure prison and isolated from the American people, where they can do no harm. America has not been attacked at home since 9/11 because of the hard work of our Armed Forces, dedicated intelligence officials, the men and women at the Department of Homeland Security, and state and local law enforcement officials.

But another reason we haven’t been attacked is because some men who are most likely to do so are locked up in Guantanamo. These inmates aren’t spectators. They’re the enemy. They’re the plotters, the planners, the funders, the ones who pull the trigger.

The administration says our country would be safer if Guantanamo is closed and its inmates are transferred overseas or onto U.S. soil. If people knew who was down there, they might disagree.

One of the men who’s locked away safely at Guantanamo is Khalid Sheikh Muhammad, the man who actually organized the 9/11 attacks. We captured him while he was planning follow-up attacks to 9/11, including a plot to destroy a West Coast skyscraper. If we hadn’t captured Khalid Sheikh Muhammad, he may very well have succeeded in carrying out the same kind of attack on the West Coast that he carried out on the East Coast.

This is a man who boasts about using his, quote, ‘blessed right hand’ to decapitate the American journalist Daniel Pearl. And he’s unrepentant: earlier this year, Khalid Sheikh Muhammad joined a number of other detainees at Guantanamo in declaring themselves, quote, ‘terrorists to the bone,’ and proclaiming September 11, 2001, as a, quote, ‘blessed’ day.

Another inmate who still declares himself a ‘terrorist to the bone’ is Ali Abd al-Azeez Ali, who served as a key lieutenant for KSM on several plots against the United States and the United Kingdom, including the 9/11 attacks. During what he describes as the, quote, ‘Blessed 11 September operation,’ Ali transferred money to U.S.-based operatives and served as a sort of travel agent for some of the hijackers. This man is responsible for the deaths of thousands of Americans.

Another terrorist at Guantanamo who is responsible for the death of Americans is Abd Al-Rahim Al Nashiri, who masterminded the attack on the USS Cole, which killed 17 U.S. sailors in 2000. When he was arrested, Nashiri was planning new terrorist attacks, including a plot to crash an airplane into a Western naval vessel and a plan targeting a U.S. housing compound in Riyadh, Saudi Arabia.

These are just three of the men locked up safely and securely on an island miles from the U.S., in a facility that even the administration acknowledges to be humane and well-run. Americans want these men kept out of their neighborhoods and off of the battlefield. Guantanamo guarantees it.

Closing this facility by an arbitrary deadline without any alternative is irresponsible and dangerous. It is unacceptable to the American people and it is unacceptable to an increasing number of lawmakers on both sides of the aisle.