Sen. Chuck Schumer (D-N.Y.) on Sunday refused to back away from his bill to impose harsh sanctions on Iran.
Schumer, who's leading a bipartisan effort to hit Iran with stricter sanctions, stood his ground, despite President Obama's recent plea not to interfere in negotiations aimed at stopping Tehran's nuclear program.
The outspoken New York senator chided the idea that Iranians came "to the table out of the goodness of their heart."
He did however, "give the president credit for talking."
Still, Schumer continued, "it's logical that it's sanctions, tough sanctions, that brought them to the table. If they think they can ease up on the sanctions without getting rid of their nuclear capabilities, they're going to do that. So we have to be tough."
The legislation would impose harsher sanctions on Iran, which has been designated a state sponsor of terrorism, if its officials fail to come to an agreement after six months.
Obama discouraged Congress from passing such legislation during the six-month window for negotiations, during which time the U.S. softens sanctions in exchange for a reduction in Iranian uranium enrichment and access for international inspectors.
At his final scheduled year-end press conference last week, Obama said, "I've heard arguments, well, but this way we can be assured and the Iranians will know that if negotiations fail even new and harsher sanctions will be put into place. Listen, I don't think the Iranians have any doubt that Congress would be more than happy to pass more sanctions legislation."
The ultimate goal would be an end to Iran's nuclear weapon program.
He added, "if we're serious about negotiations, we've got to create an atmosphere in which Iran is willing to move in ways that are uncomfortable for them and contrary to their ideology and rhetoric and their instincts and their suspicions of us. And we don't help get them to a position where we can actually resolve this by engaging in this kind of action."