With negotiations over Iran's nuclear program under way in Geneva, Congress is weighing whether to impose stricter economic sanctions that would increase pressure on Tehran to abandon its nuclear ambitions.

Sens. Mark Kirk, R-Ill., and Bob Menendez, D-N.J., the bipartisan force behind the last round of sanctions on Iran, are pressing again to tighten those restrictions. But the Obama administration, hoping to maximize its flexibility in current negotiations with Iran, is lobbying lawmakers to delay action on any new sanctions.

“They are seeking to have a delay, which is exactly what the Iranians want,” Kirk told the Washington Examiner.

The Illinois Republican argued that it is Congress’ role to squeeze Iran even as the White House negotiates with Tehran. The last round of sanctions, he noted, had unanimous support in the Senate.

“Congress plays bad cop … because common sense is more dominant here than in the bowels of the administration,” Kirk said. He said he would resist any White House efforts to delay action on new sanctions "until I'm fully assured that our children's future does not have an Iranian nuclear weapon in it."

But Kirk would not say when the legislation imposing new sanctions would be introduced — or when Congress would be expected to address the issue.

“It’s very difficult to predict,” he said of the timing. “This place is pretty lazy and doesn’t like to work hard.”

Kirk, along with Menendez, is playing a delicate balancing game. The objective: To project that "bad cop" attitude to the world while convincing other senators that the sanctions are precise and measured.

To that end, Kirk highlighted the Iranian threat while pledging that the new legislation would be “a scalpel, not a hammer." A tougher approach might have a greater effect on the Geneva negotiations, but Congress is far more likely to embrace a more measured strategy.

The point of the legislation Kirk proposes is, in his words, to help the United States “prevail over negotiations.” It would force banks around the world to choose between the massive U.S. market and the much-smaller Iranian one, he said.

The senator also dismissed the notion that Iranian President Hassan Rouhani, who was elected in June, would be much more moderate than past Iranian leaders. Kirk told a story about having lunch with now-Iranian Foreign Minister Javad Zarif and Rep. Steve Israel, D-N.Y., in June 2006.

"It was one of those long, Middle Eastern monologues, where he was just trying to run out the clock," he said.

Almost the entire time, Kirk said, Zarif lectured the two on how the Holocaust didn’t happen. Later, Zarif explained that he was ordered by his government — then led by Mahmoud Ahmadinejad — to raise the topic with the two lawmakers. Sensing his lack of enthusiasm, Kirk questioned what was going on. "I'm going to be replaced by a hard-liner,” Zarif confessed.

The point Kirk was making: Even Iranian moderates are pretty hardline, the difference between apologetic Holocaust denial and aggressive Holocaust denial.

Kirk is as pessimistic as Rouhani about the ongoing negotiations, though for Kirk those doubts arise from the belief that the president isn't being forceful enough with the Iranians.

“Most people would feel that the president is being way too weak on the Iranians. There's no upside,” he said. “There is a fundamental rule of politics: Vicious dictators will always undermine the U.S. politicians who rely on them."

For Kirk, the work on international sanctions has been therapeutic, aiding his rehabilitation and recovery from a stroke he suffered in January 2012.

He recently climbed 41 floors of the Sears Tower. And on Nov. 4, he gave his first speech on the Senate Floor since his sudden medical emergency, on the importance of passing the Employment Non-Discrimination Act.

Working on problems with Iran, he said, helps his mental rehabilitation as well.

“My work is the central driving force behind my rehabilitation,” he said. “I am completely motivated by stopping a war between Israel and Iran, making it unnecessary.”