当地时间2018年1月12日，美国总统特朗普宣布，美国仍将遵守《伊核问题全面协议》，暂时不会恢复此前因为核计划而对伊朗实施的制裁。但特朗普同时发出“最后通牒式”警告，称必须要对伊核协议进行修改，否则这将是他给予的最后一次延长制裁伊朗的豁免期，届时美国将退出协议没商量。这一表态虽暂时缓解了人们对美国单方面退出伊核协议的担忧，但伊核协议的命运仍前景不明，三个月的时间窗口之后是被美国单方面撕毁还是经修改得以继续存续，拟或排除美国而由其他签约方按照原有协议内容继续执行下去，仍不得而知。

一方面，特朗普的态度很坚决，要求对他所称的美国历史上签订的“最糟糕的协议”进行修改。据了解，其希望修改的主要内容是，永久限制伊朗铀浓缩活动、限制伊朗发展弹道导弹项目和伊朗在中东的军事动作等均纳入核谈判。另一方面，伊朗的态度同样坚决。伊朗外交部已发表声明强调，伊朗现在不会接受、未来也不会接受任何就伊核协议的修改，伊朗也不会实施超出这份协议之外的任何举措。声明还强调美国必须像其他国家一样全面履行其承诺，假如美国以各种荒谬的借口不履行这些承诺，美国将承担相关一切后果。

伊朗态度的坚决主要基于两个方面。首先是伊朗很好地履行了伊核协议规定的义务。自2015年7月伊核协议签署以来，国际原子能机构的历次报告也都认可了这一点，即便特朗普政府在向美国国会报告时，似乎也很难从伊朗执行协议的过程里挑出什么瑕疵。其次，伊核协议是一项国际多边协议，是由包括美国、俄罗斯、中国、德国、法国、英国在内的六方与伊朗经过艰难谈判达成并由安理会认可通过的多边国际协议。目前，除了美国一方提出修改协议并威胁“退群”以外，其他签约各方均支持伊朗的主张并力挺协议的继续实施。

特朗普态度的坚决也主要基于两个方面。一是兑现其竞选承诺。从参与竞选到就任总统以来，特朗普一直对伊核协议表达强烈不满，称协议对美国而言是灾难性的，并始终威胁要退出协议。伊核协议是奥巴马的“外交遗产”，特朗普上台后推出的各项政策实际上都是在对奥巴马的“遗产”进行否定式“清零”，如修改医改法案、退出TPP、退出《巴黎协议》等等。二是，特朗普政府毫不掩饰地把伊朗作为美国中东战略的主要对手和敌人。特朗普总统执政以来不断加大和加强与以色列和沙特的战略盟友关系，把以、沙两国视为美国中东战略倚靠的重要盟友和支柱。而以色列和沙特不仅一直是伊朗的战略竞争对手，而且都对奥巴马政府签署的伊核协议不满，希望修改并撕毁该协议。

事实上，伊核协议目前最需要的是保护和继续推进，而绝不是退出和撕毁。协议的撕毁不仅对当事国伊朗不利，而且对美国及其中东盟友以色列和沙特同样不利，对国际核不扩散努力也是一个沉重打击，其最终结果只会是负面和多输。对伊朗而言，协议的撕毁将激发国内保守派的新一轮反美浪潮，并可能迅速启动其报复性的铀浓缩等核能研发进程，并阻断其刚刚开启不久的与世界接轨和开放的大门，加剧伊朗与西方的对抗。对以色列和沙特而言，伊朗核能研发的重启自然增强了两国的战略疑虑和不安全感，同时也会刺激两国同步进行核能研发，从而导致中东地区的新一轮军备竞赛和不稳定。对美国而言，单方面撕毁多边国际协议不仅会失信于天下，严重损害美国的国际信誉、国际形象和“软实力”，而且不利于美国参与谈判解决类似朝核问题的其他国际热点问题。最后，对国际和平与安全而言，伊核协议这一历史性协议的达成不仅是有关各方长期艰苦谈判的结果，是符合各方利益的多赢协议，它更是多边主义、和平主义和理性主义的胜利，是外交智慧、国际合作以及用和平谈判手段解决棘手的核问题的成功先例。这样成功且来之不易的国际合作成果，更需要有关各方精心呵护，使其走的更稳和更远，为世界面临的其他类似问题发挥示范和表率作用，而不是釜底抽薪，以单方面不负责任的撕毁协议让多年国际合作和努力化为灰烬。

目前，除美国以外的其他五个伊核协议签署国均表示要继续维护和执行协议。至于美国提出的有关伊朗发展弹道导弹项目等问题，因其与伊核问题无关，因此不需要掺杂到伊核协议里面来谈，使原有问题复杂化，而是应该在协议以外的其他机制里来谈判解决。

On 12 January 2018, President Donald Trump announced that the US would still honor the terms of the Joint Comprehensive Plan of Action with Iran and waived sanctions one more time. But he also issued an 'ultimatum': the agreement must be revised or US will withdraw from it. The future of that deal remains uncertain. Will it be scrapped by the US after three months or be retained with revisions? Or will the other signatories of the deal follow its original terms?

On the one hand, Trump's attitude is quite firm in demanding revision of what he described as the 'worst' accord in American history. The revisions he wants reportedly include permanent restrictions on Iran's nuclear enrichment activities, restrictions on its ballistic missile program, and inclusion of its military operations in the Middle East in the nuclear negotiations. On the other hand, Iran also has a firm attitude. The Iranian Foreign Ministry has already issued a statement, stressing that Iran does not and will not accept any revision to the agreement and that Iran will not implement any measures outside of the agreement. It also stressed that the US must fully uphold its commitment like other parties to the agreement and bear all the consequences if it fails to do so under any absurd excuse.

There are two reasons behind Iran's firm attitude. First, Iran has met its obligations under the nuclear agreement, which has been supported by IAEA reports. Even the Trump administration, reporting to Congress, has found it hard to find flaws in Iran's implementation. Second, the Iranian nuclear deal involves a multilateral agreement concluded through tough negotiations between Iran and the US, Russia, China, Germany, France, and UK and endorsed by the UN Security Council. At present, only the US has proposed modifying it and threatened to withdraw, while all other parties support Iran's desire to continue implementing the agreement.

There are also two reasons behind Trump's firm attitude. The first is his campaign promise. Since the beginning of his campaign, Trump has complained about the Iranian nuclear deal, describing it as disastrous to the US and threatening to withdraw. The agreement is President Barack Obama's diplomatic legacy. Since taking office, President Trump has introduced various policies to negate Obama's legacies, including the Obamacare reforms, and withdrawal from the TPP and Paris Climate Agreement. Second, the Trump administration makes no secret that America regards Iran as its main adversary in the Middle East. President Trump has consistently increased and strengthened strategic ties with Israel and Saudi Arabia, its two important allies in the region. These two countries are Iran's strategic competitors and have expressed unhappiness over the deal with Iran and hope to revise or scrap it.

As a matter of fact, what the agreement needs most now is protection and continued implementation. Withdrawal which will hurt not only Iran but the US and its Middle East partners, i.e., Saudi Arabia and Israel, and deal a heavy blow to the international nuclear non-proliferation regime. In Iran, scrapping the agreement will stimulate another wave of anti-Americanism among the conservatives which may well lead to prompt reactivation of uranium enrichment and other nuclear R&D activities, interruption of its nascent effort to open to the outside world and increased confrontation with the West. For Israel and Saudi Arabia, Iran restarting nuclear energy research will increase their strategic misgivings and sense of insecurity and stimulate them to do the same, thus triggering a new arms race and increasing instability in the Middle East. For the US, unilaterally scrapping a multilateral agreement will seriously undermine America's international reputation and soft power, thus harming US participation in the negotiated solutions of other similar international issues. For international peace and security, the historic nuclear agreement was the result of a long, arduous negotiation between the relevant parties. It was a win-win deal serving all parties' interests. It was a victory of multilateralism, pacifism, and rationalism and a successful precedent for resolving tough nuclear issues through international cooperation and negotiation. Irresponsible unilateral scrapping of the agreement will turn years of international cooperation into dust and ashes.

At present, all five other powers involved in the agreement have stated their willingness to continue honoring the Iranian nuclear agreement. The question of Iran developing a ballistic missile program, which was raised by the US, has nothing to do with the nuclear issue and should not be brought in to complicate the situation. It should instead be addressed through negotiations in external mechanisms.