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Iran has increasingly become one of the Obama administration's top talking points in the case for military action against Syria.

"Iran is hoping you look the other way," Secretary of State John Kerry bluntly told members of the Senate Foreign Relations Committee today. "Our inaction would surely give them a permission slip for them to at least misinterpret our intention if not to put it to the test."

In his Rose Garden remarks on Saturday, President Obama did not mention Iran a single time in announcing his decision to take action, only indirectly referencing the message that will be sent to "governments who would choose to build nuclear arms."

Today, however, Kerry mentioned Iran four times in his brief opening statement before the committee, repeatedly tying U.S. action in Syria to deterrence of Iran's nuclear threat. He said a U.S. strike against the Bashar al-Assad regime would send a clear signal about the seriousness of American opposition to weapons of mass destruction.

Asked directly whether the Obama administration might use congressional authorization to target Syria's WMD to also confront threats in other countries, such as Iran's nuclear program, Kerry said explicitly "no."

Still, influencing Iran is clearly becoming a top objective of supporters of U.S. military action in Syria.

"Our refusal to act would undermine the credibility of America's other security commitments, including the president's commitment to prevent Iran from acquiring a nuclear weapon," testified Defense Secretary Chuck Hagel.

Several members of the Senate committee, on both sides of the aisle, appeared to share the administration's recognition that inaction in Syria would embolden Iran.

"Iran will view us as a paper tiger" if we don't act, warned Sen. Barbara Boxer, D-Calif.

Doing nothing "would guarantee … an emboldened Iran," said Sen. Marco Rubio, R-Fla. "It will also send a message to the world that there is no red line that they should fear crossing. So Iran will move forward toward nuclear weapons."

It's a message Sens. John McCain, R-Ariz., and Lindsey Graham, R-S.C., delivered personally to President Obama when they met with him at the White House on Monday.

A White House official told ABC News that Iran will figure prominently in outreach to members of Congress in the coming days.

Individual and conference calls will focus on the "fundamental case that failure to take action … risks emboldening Assad and his key allies - Hezbollah and Iran - who will see that there are no consequences for such a flagrant violation of an international norm," the official said.

"Anyone who is concerned about Iran and its efforts in the region should support this action," the official said.