One year ago, President Barack Obama received a standing ovation from the pro-Israel lobbying group American Israel Public Affairs Committee (AIPAC) when he sternly committed to preventing Iran from obtaining nuclear weapons. Containment of Iran, the president said, is not an option, adding that on his watch, Tehran would never be allowed to construct a nuclear device without dealing with the threat of military force first.

Twelve months later, Vice President Joe Biden laid out the same policy to an AIPAC conference. As if to underscore just how serious the United States consider a nuclear armed Iran, Biden framed his remarks in a blunt but strong tone: American policy is, and will continue to be, “to prevent Iran from acquiring a nuclear weapon. Period. Period. End of discussion.”

In terms of American foreign policy, there is nothing new in Biden’s vow. President Obama, after reaching out to the Iranian leadership during his first year in office in the hope of sweetening a relationship that has been one of the world’s most antagonistic for the past thirty years, has been one of the toughest presidents on Tehran in modern times.

Whereas Iran largely ignored the George W. Bush Administration and basked in the comfort of an overstretched American military while the Republican was in office, it has taken the Obama Administration seriously.

Partly as a result of the president’s success in forging an international sanctions regime, the Islamic republic is suffering one of the most painful economic periods in its history. The country’s oil exports have been slashed in half and its economy is losing billions of dollars every month.

All of this, in essence, to turn up the pressure to such an extent that Ayatollah Ali Khamenei and his government will be coerced into scaling back the nuclear program.

While his comments may therefore not appear newsworthy, Vice President Biden’s statements are still significant, particularly at a time when Iranian negotiators are back at the table for discussions about their nation’s uranium enrichment program.

The vice president has very little, if any, influence on how these multilateral talks, that include representatives of the five permanent members of the United Nations Security Council plus Germany, progress but his tough rhetoric about using military force to curtail the building of an Iranian nuclear bomb could nonetheless negate the positive remarks that were produced during the most recent talks.

Coupled with a joint United States Senate resolution that would have the country actively back up Israel were it to strike Iran militarily, the very Iranian diplomats who spoke of “a turning point” in the negotiations could just as quickly scurry back into their corners.

The Iranians are not without blame. Ayatollah Ali Khamenei’s defensive language equating the West to a paper tiger trying to bully the rest of the world is not the sort of comment that helps the negotiating atmosphere. Nor are statements from senior Iranian officials about teaching Israel a lesson.

But when lawmakers in Congress push through uncompromising legislation on the Iranian nuclear issue and top White House officials constantly remind the Iranians that bombing them is a realistic option, there is a decent chance that the fractious government in Tehran will use the language as an excuse to ramp up its uranium enrichment efforts and perhaps cut negotiations short altogether.

If the talks are to succeed, both Iran and Western powers will have to tone down their rhetoric.