Sen. John McCain (R-AZ) said today he's "very worried" about a court ruling that found the NSA's massive surveillance program to be illegal.

"We have to understand this threat and people seem to have forgotten 9/11," he said. "People don't understand that there are thousands of young people all over the world who are motivated by this radical brand of Islam, which is our enemy."

McCain recalled that 9/11 could have been prevented if the government had the ability to monitor communications. 

But he said that he believes Congress and the American people can have a debate about NSA monitoring and come up with a system that has the right "balance."

He also reacted to ISIS purportedly claiming that it has 71 trained soldiers in 15 states across America. 

McCain said that he thinks ISIS is recruiting young people through social media and building relationships with them online.

"It is a tremendous challenge, because of the penetration and the ability of social media to brainwash and to motivate these young people to commit acts of terror and/or flock to...Syria, Iraq to fight and then they'll come back," McCain stated. 

He asserted that as long as ISIS is perceived to be succeeding, they're going to be attracting young men and women who want to fight.

Watch the full video above.

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