On January 3, US President Donald Trump announced triumphantly the killing of Iran's General Qassem Soleimani. Having assassinated the equivalent of a member of the US Joint Chiefs of Staff, Trump claimed he did not want war. His words rang hollow in Tehran where this brazen attack was seen as an act of exactly that.

As many have noted so far, the assassination was carried out to help Trump's struggling re-election campaign. This strategy could have worked if Iran was a static player on the chessboard.

But it is not and depending on how it chooses to retaliate and the course of action it adopts vis-a-vis the US in the coming months and years, it could determine Trump's political fate. This episode along with other impulsive actions by the president will negatively affect the United States's regional position and its global role more broadly.

Only hours after the assassination, Iran's Supreme Leader Ayatollah Khamenei stated that "a harsh revenge awaits the criminal killers". And after a meeting headed for the first time by him, Iran's supreme national security council issued a statement saying "the US regime will be responsible for all the consequences". If Trump expected Tehran to swallow the pain, he obviously miscalculated.

Soleimani was by far the most popular official figure in Iran; according to a 2019 poll, 82 percent of Iranians viewed him favourably. His assassination brought the nation together and made the need for revenge that more urgent. Beyond taking vengeance, a gradual shift in Iran's strategic conduct vis-a-vis the US and its client states in the region is expected - one that will be less tolerant of the US presence.

Soleimani rose to prominence from the lowest ranks in the Islamic Revolutionary Guard Corps (IRGC) in the 1980s and fought all of Iran's adversaries beginning with the Baathist Regime in the Iran-Iraq war all the way to ISIL (ISIS).

He was the architect of Iran's "forward deterrence" in the region that rendered US anti-Iran efforts feckless and helped defeat ISIL. Soleimani's strategic vision was widely seen as essential to Iran's defence. Assassinating him, therefore, targeted first and foremost Iran's national security in the eyes of both Iranian officials and the Iranian public.

Hours after the assassination, Soleimani's deputy, Esmail Qaani, was appointed the new commander of the IRGC's Quds Force. The move was meant to refute speculations about a vacuum left behind by Soleimani but also to emphasise the continuation of Iran's regional strategy of "forward deterrence".

After the assassination, the Iranian leadership started debating when, where and how rather than whether or not to retaliate. Tehran is compelled to respond as its inaction would render its regional deterrence irrelevant, weaken "the axis of resistance" - the alliance of like-minded Middle Eastern states and political-military movements allied with Iran - and encourage the US's escalation.

Iran's geographic position, regional alliance and military capabilities, demonstrated recently in the downing of the sophisticated US spy drone in November and the targeting of ISIL positions in eastern Syria in 2016-17, gives it a wide range of options to respond.

The barrage of missiles which hit US bases in Iraq on January 8 was just the beginning - just a "slap" according to the Iranian Supreme Leader - and it seems to have been meant as a quick response to satisfy the public's cry for revenge. It fell short of being proportional to the assassination of Soleimani, which means one should expect more to come.

Iran is not likely to resort to rash action in the face of US escalation. It will most likely sleep on its options for quite some time before launching its response which will be marked by the traditional gradualism and steadiness of its regional conduct. Re-establishing deterrence on a new level would be the main objective of Iran's new course of action vis-a-vis the US escalation.

Though varied, Iran's options are all hard choices that can lead to further escalation. The US backing down after the January 8 missile attacks on its positions in Iraq decreased this possibility for now, but in the future, a tit-for-tat can easily spiral into a confrontation

Iran's main options include an increase in asymmetric warfare on an unprecedented scale to bleed the US in the region. Feeling attacked in Baghdad, the entire axis of resistance can be engaged in such a scenario.

Tehran might also resort to a devastating attack on one of the US's client states such as Israel - as alluded to in the IRGC statement after the missile attacks in Iraq - that diminishes any sort of deterrence Washington thought the assassination could establish.

Other Iranian options include cyberattacks and indirect attacks on US assets and forces in the region.

Tehran knows that continuing domestic and international debates on Trump's foreign policy misconduct during this time can increase internal pressure on him, which it hopes to take advantage of.

It will try to show the American public, Trump's rivals within the US as well as its clients in the Middle East that the assassination will not in any way serve US interests or those of its allies. In doing so, Tehran will be pushing Trump into the hard place he tried to put Iran in: A retaliation would work against his campaign promise of pulling out of wars, while inaction would harm his reputation.

With Trump ordering the assassination as a way to show his decisiveness after being criticised for inaction against Iran's downing of the US spy drone, Iran's new course of action is likely to focus on hurting his reputation. Over the course of this year, this can affect his re-election campaign or taint his second term.

Soleimani's assassination also precluded any chance for a diplomatic win in the Middle East for the Trump administration.

In 2018, Trump killed the Iranian moderates' momentum by pulling out of the Iran nuclear deal and by reimposing sanctions. He has now killed the prospect for any future negotiations under his administration.

Iran has already shown signs it is willing to resurrect its nuclear programme. Declaring Iran's fifth step in reducing its Joint Comprehensive Plan of Action commitments, President Hassan Rouhani announced Tehran's move beyond many of its restrictions.

With public demand for revenge, Iranian missile attacks on US positions in Iraq and urgent geopolitical considerations Iran has to address, it is hard to imagine the re-start of negotiation with the US in the years to come.

The views expressed in this article are the author's own and do not necessarily reflect Al Jazeera's editorial stance.