Iran, North Korea and Afghanistan are three major and interlinked challenges confronting the Biden administration.The US is already in a diplomatic battle with Tehran. With Israel pushing from the sidelines, it is a question of who will blink first and concede to demands of the other side as a condition for returning to the 2015 nuclear deal. On Thursday, North Korea carried out its second weapons test, and the first ballistic missile test, of Biden’s term, forcing Washington to respond.Many analysts who downplayed an earlier weapons test, saying it did not violate UN resolutions, pointed out that this new ballistic missile test does violate those resolutions.How will the US respond and how will this impact Israel and the Iran nuclear issue?On May 1, the Biden administration will need to decide whether to fulfill a Trump administration commitment to withdraw American troops as part of an effort to enforce a ceasefire with the Taliban, or to ignore that commitment, since many say the Taliban have violated their key commitments in recent weeks.Although technically each issue stands on its own and they are playing out in different parts of the world, Iran and North Korea have long been seen as running in parallel as the top nuclear challenges facing the world today.Israel and the Islamic Republic have both kept a very close watch on developments with Pyongyang to tease out how tough a stand the US will take on nuclear issues.How strong or weak Washington looks versus North Korea can sometimes reflect how it will act toward Tehran.So far, the Biden administration has done all it can to keep the North Korean issue on the back burner.When top Pyongyang officials have issued threatening statements, Washington has either refrained from responding or tried to reduce the decibel level of public exchanges.This is in stark contrast to the Trump administration, which often responded to North Korean threats with larger threats to wipe out leader Kim Jong Un and his regime.In fact, after the initial North Korean weapons test, the Biden administration coordinated with South Korea to keep a low profile.The latest North Korean ballistic missile test may have been not only a general test of Washington’s resolve but also a response to US joint exercises with South Korea.Yet, those joint exercises themselves have been very low-key. This may continue a Trump-era unwritten deal of no high-profile joint exercises in exchange for no high-profile missile actions.Even the latest ballistic missile tests are a far cry from past North Korean tests of intercontinental ballistic missiles, which might be able to hit the US, and actual nuclear bomb underground tests.Afghanistan has no nuclear weapons. But it provides the most immediate test of whether the Biden team will choose more military or more diplomatic means when under pressure.Some will push for the US to project power when faced with violations of international law and Western interests.Others will try to explore diplomatic means to a much greater extent, arguing that after the bluster of the Trump era, the Biden team must strive to prove the US can resolve conflicts at the negotiating table.If the US fully withdraws its troops despite ongoing Taliban cooperation with al-Qaeda and despite ongoing attacks on US-allied forces, the message to Tehran and Pyongyang will be that the Biden administration may wilt under pressure over time.By this reading, even if Washington may show some initial resistance to save face, ultimately the current administration could be seen as being anxious to avoid much low-grade conflict.From this perspective, Israel, which has little interest in Afghanistan, may prefer that the US remain there to signal its readiness to take risks when demanding policy shifts from adversaries.Of course, the US could risk being stuck in an unending quagmire in Afghanistan, in a war dating back to 2001, in which it may end up on the losing side.But from an Israeli perspective, it would be a message to the Iranians that the US will not run because of a bloody nose and still views itself as the world’s leading power.There are also in-between options, such as a continued partial drawdown of troops, conditional on the Taliban actually cutting itself off from al-Qaeda.Interestingly, in both the North Korean and Iranian cases, Biden has attempted either formal or informal diplomatic moves to get negotiations started, and in both cases, he has gotten the cold shoulder.Will Biden make greater concessions to Kim Jong Un to get him to the negotiating table? If so how might this impact Iran?Or will Biden bide his time with Pyongyang as he is currently doing with Tehran in a longer-term test of wills?The image of Biden’s foreign policy toward aggressive adversaries is still unfocused and developing.Jerusalem is a bystander on some of these issues, but would much rather the US project strength.Ultimately, there is no question that the way Biden addresses the current North Korean flareup, as well as the Taliban pressure in Afghanistan, will either strengthen or weaken his hand in dealing with the Islamic Republic over the nuclear standoff.