Those concerned about how long it will take to achieve President Obama’s goal of destroying Islamic State, also known as ISIS, will not be buoyed by news of the militant extremists’ rapidly rising numbers. A CIA spokesman told the Associated Press the group known for its brutal tactics can now muster between 20,000 and 31,500 fighters. That’s a big increase on the agency’s previous estimate of 10,000 jihadists, and higher even than the 20,000 figure cited by some outside experts. The reason is also alarming: stronger recruitment by ISIS since June, following the group’s declaration of an Islamic caliphate incorporating parts of Iraq and Syria. To put things in perspective, 31,500 fighters is more than many smaller countries have in their entire military. The United Nations is considering a proposal that would require countries to enact laws that rein in recruitment of foreign fighters.