As the old Israeli saying goes, “What you don’t see with your eyes, don’t invent with your mouth.”

Iran and six world powers, including the United States, are meeting in Geneva to negotiate over Iran’s nuclear weapons program. The US must be clear and unequivocal: There will be no reductions in sanctions without verified steps to show that Tehran is abandoning, not just freezing, its nuclear weapons program.

Sanctions are what have brought Iran to the table to talk in the first place. In 2012, the Islamic Republic’s net exports of petroleum dropped to their lowest level since 1990. Its GDP has dropped for the first time in 20 years. The Iranian Central Bank acknowledged an annual inflation rate of 45 percent in late July 2013; many economists believe it is more likely in the 50-70 percent range.

In short, the Iranians are feeling the pinch. The sanctions are working.

But getting the Iranians to the negotiating table is not good enough.

If we reduce sanctions now, we give up one of our main sources of leverage for the negotiations. Why stop what is working before we even start talking? Tehran wants to ease the sanctions to a tolerable enough level so that it can continue developing nuclear weapons without pain to its economy.

If we ease sanctions now, Iran will doubt our resolve, continue to run out the clock, and develop nuclear weapons knowing that there will be no serious consequences.

If the US caves in at this critical time, other countries around the world will likely follow its lead and ease their own sanctions. In short, we would be right back to where we were in 2004: Iran marching toward a dangerous nuclear weapons program with no significant sanctions in place. Only this time, it would be much worse. Tehran has continually blocked international inspectors from seeing its nuclear facilities because it has something to hide.

Iran is closer than ever before to crossing the threshold and developing a nuclear weapon. Iran’s stockpile of medium-enriched uranium has nearly doubled in a year, and its number of centrifuges has expanded from 12,000 in 2012 to 19,000 today.

Iran could produce enough weapons-grade uranium to build a nuclear bomb in as little as a month, a recent report by the Institute for Science and International Security states. It goes on to say that if Iran built a covert enrichment plant with the specific purpose of enriching uranium as quickly as possible, with current Iranian technology it could produce enough material for a nuclear bomb in a week. Backing off from sanctions now should not be an option. We simply do not have time.

If we want diplomacy to succeed, we shouldn’t be talking about reducing sanctions but rather ratcheting them up. My colleagues and I in the House of Representatives passed an additional sanctions bill in July that would inflict even more pain on the Iranian regime. These new sanctions would go after more sectors of the Iranian economy and more individuals in the Iranian government. The US Senate should ignore the president’s objections and pass these sanctions immediately. If peace is to carry the day, we cannot start backing down now.

Nobody wants war with Iran. We should not give up the one peaceful tool that has finally impacted the Iranian regime enough to change its cost-benefit analysis. It would be foolish and dangerous to reduce sanctions without Iran proving that it is dismantling its nuclear weapons program. And that’s just the way it is.