The Israeli attack on a previously undisclosed active Iranian nuclear weapons research facility demonstrates that Iran is trying to reduce the timeline to develop nuclear weapons if it chooses, meaning Israel and possibly the United States will be more likely to attack Iran again. Israel's Oct. 26 strike on Iran included an attack on an active nuclear weapons research facility at the Parchin military complex, located about 20 miles (about 32 kilometers) southeast of Tehran, Axios reported Nov. 15, citing both Israeli and U.S. officials. The strike on the Taleghan 2 facility at Parchin destroyed equipment that helps design a nuclear trigger's plastic explosives surrounding uranium. The facility was top secret such that only a small part of the Iranian government knew about the scientific activity being undertaken there, according to a U.S. official. Although the Biden administration pressed Israel to refrain from attacking Iranian nuclear facilities, the Taleghan 2 facility appears to have been chosen because its undisclosed nature meant that Iranian leaders could only acknowledge and claim the attack targeted Iran's nuclear program by also admitting that they had violated the Nuclear Non-Proliferation Treaty and had a more active program than publicly acknowledged. 

• Israeli and U.S. intelligence agencies detected suspicious research activity in Iran, presumably at the Taleghan 2 facility, earlier this year, though U.S. sources initially said its purpose was unclear. The United States privately warned Iran to stop the activities, but they continued. 
• In August, The Wall Street Journal also reported that a report by the Director of National Intelligence submitted to Congress omitted a sentence previously included in similar intelligence assessments that said that Iran "is not currently undertaking the key nuclear weapons-development activities necessary to produce a testable nuclear device." 

Conflict between Israel and Iran and its proxies over the last year has only reinforced to Tehran that it needs to keep the option to develop nuclear weapons open and look at ways to reduce the timeline of developing a nuclear weapon. Iran's nuclear strategy has long been a hedging strategy where Iran carries out nuclear research for civilian purposes, like uranium enrichment and processing for a nuclear reactor, that could be repurposed or used to develop a nuclear weapon should it so choose. Iran's senior leaders now appear to be assessing that there is a higher likelihood in the future that they will need to develop nuclear weapons in the wake of the conflict with Israel. Israel's dismantling of Iranian proxies Hamas and now Hezbollah has weakened Iran's so-called Axis of Resistance deterrent to Israeli and U.S. strikes on Iranian soil. Although the resumption of activities at the Taleghan 2 facility began prior to Israel's second strike Oct. 26, Israel has also now twice demonstrated that it is willing to carry out strikes inside Iran and accept the consequences. Since the strikes, Iranian leaders have increasingly openly floated the possibility of Iran changing its nuclear doctrine. Nevertheless, the research activities at the Taleghan 2 facility, at least based on publicly leaked information, do not constitute a full resumption of Iran's nuclear weapons program. The decision to carry out the computer modeling, metallurgy and explosive research on explosives needed to set off a fission reaction demonstrates that Iran is now more interested in carrying out activities beyond research more closely related to civilian applications. These activities aim to decrease the timeline between Supreme Leader Ali Khamenei's authorization of a nuclear program and the assembly of a first device. This strategy is similar to how Iran has been stockpiling uranium enriched to 60% U-235, which would enable Iran to more quickly enrich uranium up to the 90% U-235 considered weapons grade. 

• Before the research modeling activity detected earlier this year, U.S. officials had said that Iran's nuclear weapons program's activity ceased in 2003 and had not resumed. But even under the cover of its publicly disclosed civilian nuclear program, Iran in recent years had begun to carry out activities that most in the West view as unnecessary for civilian nuclear technology applications, including the decision to enrich uranium well beyond 20% U-235 and reopen research into uranium metal — both of which are largely unnecessary for nuclear energy and medical applications. 
• Iran's enrichment of uranium to 60% U-235 vastly reduces the timeline it will take to enrich uranium to 90% because most of the separative work units — a measurement of the enrichment work needed to separate U-235 from U-238 isotopes — needed to enrich uranium to 90% U-235 occur well before uranium is enriched to 60% U-235. 

Ultimately, Iran's decision on if and when to develop nuclear weapons will be heavily influenced by the Trump administration's Iran policy and to what extent it supports, or at the very least refrains from trying to curtail, Israeli threats to Iran directly. Early indications suggest Iran is becoming more likely to develop nuclear weapons, which would risk triggering more frequent Israeli — and potentially U.S. — strikes on Iran. Thus far, incoming U.S. President Donald Trump's selections for his foreign policy and national security team, especially Senator Marco Rubio as secretary of state and Congressman Mike Waltz for national security adviser, suggests a full return to the previous Trump administration's so-called maximum pressure campaign. This strategy — which involved expanding sanctions against Iran, exiting the 2015 nuclear deal with Iran and designating the Islamic Revolutionary Guard Corps a foreign terrorist organization — triggered the start of the significant escalation between the United States (and to a certain extent Israel) and Iran over the six years since 2018, when the United States exited the nuclear deal. The Trump administration's likely strong support for Israel will likely embolden the latter to carry out more covert and occasionally overt activity targeting Iran's nuclear and missile programs inside of Iran, and will open the door wider for Israel to continue degrading Iran's proxies abroad. Nevertheless, despite the Trump administration's and Israel's strategies likely reinforcing Iran's strategic interest in its nuclear hedging strategy or driving it to develop nuclear weapons, the Israeli attack on the secretive activities at the Taleghan 2 facility also further demonstrates how deeply U.S. and Israeli intelligence agencies have penetrated Iran's nuclear program. This means that if Iran secretly begins developing a nuclear weapon or carrying out additional nuclear weapons research, the United States and Israel will find out relatively quickly. Depending on the level of significance and how quickly they could result in a nuclear weapon, Israeli and perhaps even U.S. military strikes on the facility could ensue designed to set back Iran's research activities. Doing so would both increase the likelihood of a regional conflict and also ultimately reinforce Iran's interest in developing nuclear weapons. This is especially true since any setbacks to its nuclear weapons program would likely be temporary, requiring more Israeli or U.S. strikes to set back the program for longer — further demonstrating to Iranian leaders that their prior deterrence strategy has failed and thus incentivizing a push toward a bomb. 

• While the Trump administration is far more likely to pursue an aggressive campaign against Iran, there is a low likelihood possibility that Iran and the United States will engage in some level of nuclear negotiations. Iranian officials are reportedly debating whether to engage with the Trump administration in talks. Sky News Arabia reported Nov. 13 that Iran had delayed its retaliation for Israel's Oct. 26 attack on Iran in an effort to open negotiations with the United States under Trump. For Iran, negotiating a new nuclear deal with a Republican government — despite its typically more hard-line position — is somewhat desirable because it would increase the likelihood that the agreement survives future U.S. administrations, unlike the 2015 deal negotiated with former President Barack Obama. 
• Trump has hinted on several occasions that he is open to negotiating with Iran, and on Nov. 11 Elon Musk met at a secret location with Iran's ambassador to the United Nations in an effort to defuse tensions between the United States and Iran. The likelihood of a deal remains low, however, since the Trump administration is likely to have a maximalist position that includes demands for Iran to completely dismantle its nuclear program and reduce or eliminate support for overseas militias like Hezbollah. With next to no trust between the United States and Iran, Tehran is highly unlikely to accede to everything the Trump White House wants because that would reduce the power of Iran's deterrence and its ability to develop a nuclear weapon in the future if relations between the two, as well as between Israel and Iran, deteriorate again.