He also called the recently passed House bill ordering new restrictions on Syrian and Iraqi refugees seeking to settle in the United States "an appropriate response" to the Paris attacks.
The House bill doesn't outright ban the admission of those refugees -- which Rubio, a Republican presidential candidate, has said he wants. But Rubio said on "Fox News Sunday" that most people -- with the exception of examples like "a 5-year-old orphan" and "a 90-year-old widow" -- won't be able to meet those stricter vetting requirements and therefore won't be allowed into the country.
"My argument is that we can't allow anyone in this country that we can't vet. And I believe that the vast majority of refugees that are trying to come here are people that we will not able to vet," Rubio said.
Rubio also defended his opposition to a measure in 2013 that would have authorized Obama to use air strikes against Assad in the wake of Assad's use of chemical weapons against his own citizens.
Rubio said he still doesn't support air strikes against Assad -- and that the move he supported then and now is to arm moderate Sunni rebels in a fight against Assad's regime.
"He would have survived. He would have remained in power. And it would have strengthened his hand and allowed him to send a message to the world that he had taken on the United States and still held on. In fact, it may have even rallied some in the Arab world to his side as a result of such a strike," Rubio said.
"No one's calling on air strikes on Assad now," he said, "and I thought it was wrong then, too."
Rubio said while he's not happy about the Paris attacks, he thinks it's a "positive development" in that it has pushed the political conversation to national security.
"As far as national security, let me just say, I obviously am not happy about the events that happened last week in Paris," Rubio said. "But I think it's a positive development that it suddenly has forced Americans to confront more carefully the issue of national security, because it is the most important thing a president will do and it's the most important function of the federal government."
"And I hope that we focus on that more, not just for political advantage, but because the world has become a very dangerous place," he said.
Rubio, who is climbing in Republican presidential polls, had more tough talk for ISIS and terrorist groups in the first television advertisement by his campaign, which was released Sunday but won't begin airing until Tuesday.
In the spot, Rubio says that "there can be no arrangement or negotiation -- either they win or we do."
"This is a civilizational struggle between the values of freedom and liberty, and radical Islamic terror. What happened in Paris could happen here," Rubio says in the ad. "There is no middle ground. These aren't disgruntled or disempowered people. These are radical terrorists who want to kill us, because we let women drive, because we let girls go to school."
The campaign did not provide details about the size or scope of the buy except to say it will be running "nationwide."