The joint U.S.-Israeli "preemptive" military strike on Iran on February 28 – which resulted in the killing of Iran's Supreme Leader Ayatollah Ali Khamenei – has triggered sharp criticism both at home and abroad, raising concerns about regional stability and the broader implications for global security.

International fears of escalation

Many countries have condemned Washington's unilateral use of force, arguing that it violated Iran's sovereignty and calling for restraint. Analysts warn that regardless of U.S. and Israeli intentions, the attack risks plunging the Middle East into a new period of uncertainty and volatility.

Galip Dalay, a researcher at the Royal Institute of International Affairs (Chatham House), cautioned in an article published by the think tank this week that the fallout from a potential state collapse would far surpass the turmoil the Middle East has endured from conflicts in Iraq, Syria or Yemen. Such consequences, he wrote, could include "instability, migration, radicalism, the proliferation of armed groups and regional spillover."

Dalay said that the United States must give regional diplomacy a genuine opportunity to succeed. Failing that, he warned, the alternative could be "a devastating war and another catastrophic cycle of conflict."

Zhou Dewu, former deputy editor-in-chief of Ta Kung Pao, told CGTN that "wars are rarely ended by the initiator; they end when the attacked side accepts defeat." He described the U.S.-Israel assault as opening "Pandora's box."

If Iran's new leadership refuses reconciliation and instead turns to asymmetric retaliation, including possible terrorist tactics, Zhou said the region could face a new wave of extremism. He also argued that the military operation and targeted killings of foreign leaders set a dangerous precedent in international relations, creating a "chilling effect" in global politics.

According to Zhou, such actions will also accelerate an arms race, as countries seek to bolster their defenses amid a growing sense of insecurity. Under the "demonstration effect," some governments could become more inclined to use force to resolve disputes, increasing the risks of global adventurism.

The timing of the strikes, coming after a third round of U.S.-Iran talks, has also deepened skepticism about diplomatic efforts. Zhou said the move widened the global "trust deficit" surrounding negotiations. "This is not only Iran's tragedy, but also a tragedy for the international community," he said.

Growing doubts at home

The military action has also drawn scrutiny within the United States. While some Americans are concerned about nuclear proliferation and regional security, public appetite for another prolonged Middle East conflict appears limited, shaped by lingering memories of Iraq and Afghanistan.

A Reuters/Ipsos poll that concluded on Sunday showed 43 percent of Americans disapproved of the strikes, while 27 percent approved and 29 percent were unsure. About nine out of 10 respondents said they had heard at least a little about the strikes.

Anti-war demonstrations were held outside the White House and in New York's Times Square on February 28, with protesters warning against being drawn into another endless war.

Criticism has also emerged from across the political spectrum. Some conservatives have questioned the financial and strategic costs of intervention, while Democrats have sharply criticized the administration for launching strikes without congressional approval.

Democratic Senator Tim Kaine described the operation as "dangerous, unnecessary and reckless," warning that it could put U.S. troops and diplomats in the Middle East at greater risk. He urged Congress to reconvene and vote on his proposed War Powers Resolution to prevent the president from committing U.S. forces to war with Iran without legislative authorization.

Former Vice President Kamala Harris also opposed the action, stating she is against "regime change" in Iran and accusing President Donald Trump of dragging the United States into "a war the American people don't want." She called the strikes "a dangerous and unnecessary gamble" and said U.S. troops were being put in harm's way for a "war of choice."

Lawmakers also said they wanted to avoid a prolonged and costly conflict reminiscent of the Iraq War, which dragged on for years and claimed thousands of U.S. lives.

"The question is: 'Is the country (Iran) going to descend in civil war? Are billions of our dollars going to be spent there? Are American troops going to be at risk?'" said U.S. Representative Ro Khanna, a California Democrat.

Many are questioning whether the operation can achieve its stated objectives – whether regime change, surrender, or forcing Iran to abandon its nuclear plans.

Democratic Senator Chris Coons said he sees little evidence that regime change can be achieved through airpower alone. "There's no example I know of in modern history where regime change has happened solely through air strikes," he said on CNN.

Senator Rick Scott, a Republican from Florida, said he hopes U.S. involvement in Iran can be completed within a month. "We're going to finish this, and if we don't, we'll be doing this in five years, in 10 years."