As the ACLU’s Ben Wizner told me in an interview back in 2009, Obama’s Guantánamo plan — long before Congress took any action — was more likely to strengthen the camp’s scheme of indefinite detention than end it, just as Obama did with so many other once-controversial Bush/Cheney War on Terror policies:
https://firstlook.org/theintercept/2015/08/12/democrats-continue-lie-obamas-failed-guantanamo-vow/