Rising tensions between the United States and Iran have put a thin line between the two countries. The unprecedented buildup of U.S. military power in the Middle East, coupled with Washington’s reliance on gunboat diplomacy, has significantly increased the risk of war—a war that would engulf Iran and the region, with far-reaching regional and global costs.

U.S. President Donald Trump has declared it is time to oust Iran’s Supreme Leader Ayatollah Ali Khamenei following Iran’s latest crackdown on protests. His administration subsequently deployed the USS Abraham Lincoln aircraft carrier and supporting warplanes to the Middle East, as well as a variety of air defense assets, including additional THAAD and Patriot missile systems.

As military assets piled up, Trump threatened that “the next attack will be much worse than the U.S. attack on Iran’s nuclear facilities last June” if Iran did not agree to a deal.

From the U.S. perspective, a favorable deal would require Iran to dismantle its nuclear enrichment program and ballistic missile capabilities while withdrawing its regional influence. Such extreme demands, coupled with Tehran’s deep distrust of negotiations with the United States, make a deal highly unlikely. Aladdin Borujedi, a member of the Iranian parliament’s national security and foreign policy committee, clarified on Monday that civilian nuclear capabilities, as well as missile and drone capabilities, represent Tehran’s “red lines.”

This does not necessarily mean a permanent diplomatic stalemate. Tehran, however, interprets the top U.S. demands as a potential threat of regime change – a view reiterated by Trump and hawks in Washington and Tel Aviv. In this scenario, another U.S. strike would pose an “existential threat” to the Islamic Republic, removing any incentive for restraint.

The impact of any U.S. military action against Iran will depend largely on the type, scale, and targeting of the attack, which could trigger a serious crisis for Iran, the entire region, and the world.

Trump supports surgical and targeted military operations that could combine leader beheadings with severe damage to Iran’s Islamic Revolutionary Guard Corps (IRGC) military bases, Basij forces (paramilitary forces under the control of the IRGC) and police stations, which are designated by the United States to shoot at demonstrators.

Any U.S. effort to impose administrative change through military means will undoubtedly lead to dangerous domestic and regional consequences. In Iran, an attack could lead to the consolidation of power. But it could also lead to a full IRGC takeover or even internal conflict.

An attack on Iran similar to last year’s would likely result in the Iranian people uniting behind the flag and rejecting regime change for a variety of reasons. First, the Iranian people are worried about a situation similar to the collapse of states in Syria and Libya. Second, there is no credible moderate opposition capable of leading change. Third, there is strong social and political cohesion within Iran.

The political institutions, the military, and the Islamic Revolutionary Guard Corps are well organized and benefit from the vast resources generated by the rentier system induced by sanctions. Furthermore, significant segments of society—particularly working-class groups often referred to as “revolutionaries”—are aligned with this structure.

If an attack succeeds in targeting the Islamic Republic’s senior leadership, it could trigger a succession crisis, create a decision-making vacuum and deepen competition within the regime. In this case, tensions between state institutions and military security entities will increase. Given the concentration of hard power in the hands of the Islamic Revolutionary Guard Corps, the potential for a military-dominated state will expand.

The United States and Israel may also try to encourage the outbreak of civil war to weaken Iran geopolitically. Last month, some U.S. officials, including Republican Sen. Ted Cruz of Texas, called for arming Iranian protesters. This situation could easily extend to armed groups, and the United States could turn to many of the armed groups that are in conflict with Iranian authorities.

Among them are Mujahideen (MEK), once designated a “terrorist” organization by the United States and the European Union (EU); the Party of Free Life of Kurdistan (PJAK), a Kurdish armed group that seeks the secession of Iran’s western Kurdistan province; Avaziaan Arab nationalist movement that supports the secession of the oil-rich southwestern province of Khuzestan; Adel Army Hezbollah (Jundallah), an armed group operating in southeastern Iran; pan-Turkic groups in the northwest pursue the Turkic alliance of Türkiye, Azerbaijan, and Iran.

Faced with Washington’s escalating rhetoric and record of regime change actions, Iran has adopted what it calls a “mad man strategy” of simultaneously sending conciliatory and confrontational signals. This gesture was evident in Tehran’s stated willingness to establish a negotiating framework with the United States and in Khamenei’s speech on Monday. warn Any military attack on Iran would trigger a “regional war,” underscoring the country’s priority to prevent regime change at all costs—even at the risk of regional and global consequences.

Iran has made clear it will retaliate, including through allied forces in the region, which could plunge Israel and Gulf states into a wider regional conflict. This would trigger political instability and economic fragility, which could trigger massive capital flight (mainly from the Gulf countries) and an increase in the flow of refugees and migrants into Europe.

Furthermore, if Iran attacks shipping in the Strait of Hormuz or energy infrastructure in the Gulf, global oil and gas prices will soar, exacerbating market volatility, creating inflationary pressures from rising energy costs and having knock-on effects on fragile economies, further exacerbating migration pressures.

In the current situation, any U.S. military escalation poses risks not only to Iran but to the entire region. Middle East history shows that once triggered, conflict can spread like wildfire, destabilizing the entire region in unpredictable ways.

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