"We've known for months that they have an external attack branch, and we knew that it was planning an attack or a series of attacks outside of their region in Europe or the United States.
"These three attacks [in Paris] were all ISIS, they were all planned for months. They all have central command and control out of Syria, and that means they're going to be trying it here. Whether or not they can get through, it's a much harder target here."
"ISIS is much more capable. There are more of them. They have more money. They have more discipline, more training.
"This is a much bigger threat than we ever faced with Al Qaeda," Clark said."
"ISIS is the most successful terrorist organization that we have in modern history. They've exceeded Al Qaeda by a factor of X some time ago. They're conducting a conventional war in Iraq and Syria where they hold large swaths of territory.
"At the same time in the last two weeks alone, they've killed and wounded over 900 people from the countries supporting the effort against them--Russian people, Lebanese people, and now obviously French people. That is unprecedented, and it's a stunning achievement," Keane said.