BEIJING, March 2 -- The U.S. Congress will soon have a guest, Israeli Prime Minster Benjamin Netanyahu, who is expected to try to convince lawmakers that a deal with Iran on its nuclear program could threaten the very existence of the Jewish state.

Despite the upcoming pressure, policymakers in Washington should have a clear mind of the potential dangers of back-pedaling on the current promising efforts for a comprehensive deal on the Iranian nuclear issue before a March 31 deadline.

Negotiations have been on and off in the past several years since Iran agreed in 2013 to come to the negotiating table with the P5+1 group, namely Britain, China, France, Russia, the United States, plus Germany.

The lengthy process has been indeed taxing experience for not only the negotiators but also the whole world given Iran's geopolitical significance at the global level.

The rare optimism showed recently by diplomats taking part in the talks, though coated with caution, makes one feel that the protracted negotiations could finally yield some tangible results.

With a new round of talks in Switzerland impending, it is widely expected that the P5+1 could succeed in reaching a deal with Iran to prevent the latter from developing a nuclear bomb, in exchange for easing sanctions on Tehran.

The momentum does not come easy and could hardly withstand any disturbances such as a surprise announcement by Washington to slap further sanctions on Tehran.

The Obama administration needs no outside reminder to know that any measures at this stage to "overwhelm" Iran will definitely cause havoc to the positive atmosphere that came after years of frustration over the issue.

While it is impossible for Washington to insulate itself from the powerful pro-Israel lobbyist this time, the U.S. policymakers should heed that by deviating from the ongoing endeavor on Iran they may squander a hard-earned opportunity by the international community to move closer to a solution to the Iran nuclear issue, for several years to come if not forever.

For those troubled minds in Israel, they should be mindful that the P5+1 negotiators have toiled in the past few years to prevent the scenario of a nuclear-armed Iran and will undoubtedly stick to the goal in the following give-and-take with Tehran.