On today's Happening Now, Arizona Sen. John McCain (R) responded to why he's been such an outspoken proponent for the use of force in the United States' reaction to Syria's perpetration of chemical weapons use.

McCain voted yesterday as a member of the Foreign Relations Committee in favor of the resolution, and he added during today's show that he believes a strike by the U.S. will accomplish desired goals. But, he also knows that convincing the American people of his belief won't be easy.

"I understand the skepticism of my colleagues ... my constituents are very skeptical [as well]," he said. "They're burned by the Iraq [war] experience ... They're very concerned about this, and they're going to have to be convinced. And so, we've got an uphill battle here."

But it's a battle he believes the country must wage in the face of Syria's actions.

"I also think at the end of the day, the option of doing nothing in the face of using chemical weapons ... is something that will give Americans pause," said McCain, later adding, "To allow [Assad] to use chemical weapons and slaughter innocent people is something we can't let go unresponded to."