Rand Paul blamed Marco Rubio for blocking an amendment to add "trust and verify" to an immigration bill that would have made it easier to check the backgrounds of people visiting the United States or getting student visas to come here.
"One lesson from the tragedy in Paris is that we have to be extraordinarily careful about who comes here," Paul said to cheers.
He reminded the audience that some of "those who came and attacked us on 911 were here on student visas."
Paul said as a result of that, he pushed to add a "trust and verify" amendment to the immigration bill that would require fingerprinting and background checks of people entering the country.
"Your Senator, Marco Rubio, opposed me," said Paul.
He said Rubio and New York Democrat Chuck Schumer had a secret pact that blocked amendments such as his.
Other highlights from his speech:
Paul sharply criticized Hillary Clinton's role in Benghazi.
"By her inaction, by her dereliction of duty she should forever be banned from being commander-in-chief."
"We continue to give billions of dollars of our money, it's not even our money we borrow it from China, to give to Pakistan."
"Can we go further into debt or will it harm us as a country? This is a debate we need to have."