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A focus group assembled by Frank Luntz found that the best moment of tonight's debate was when Marco Rubio spoke about sending terrorists to Guantanamo Bay.

Rubio said:

And then the best military in the world, which needs to be rebuilt because -- because Barack Obama is gutting our military. He's going to leave us with the smallest Army since the end of World War II, and the smallest Navy in a century, and the smallest Air Force we've ever had.

We are going to rebuild that military and that military is going to find the terrorists and destroy them. And if we capture any of these terrorists alive, they're not going to have the right to remain silent. And they're not going to go to a courtroom in Manhattan. They're going to go to Guantanamo Bay, Cuba and we will find out everything they know and we'll do so legally.

The focus group members also had some words of advice for the candidates.

Watch the clip above.

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