Why has the U.S. not bombed Iran yet?

As Israel’s Operation Rising Lion intensifies, targeting Iran’s nuclear and military infrastructure, the United States faces a critical decision: whether to launch a direct strike on Iran’s heavily fortified Fordo nuclear facility. The operation, requiring B-2 stealth bombers armed with 30,000-pound bunker-buster bombs, is technically feasible but fraught with risks that have given pause to every U.S. president since the site’s discovery in 2009. President Donald Trump, despite his bellicose rhetoric, signaled caution on Wednesday, telling reporters, “I may do it, I may not do it. Nobody knows what I’m going to do.”

The potential for a U.S. strike, which only the B-2’s massive ordnance can execute against Fordo’s half-mile-deep centrifuge halls, has been meticulously studied. Yet, experts warn the greatest dangers lie in the aftermath, echoing the unforeseen consequences of U.S. interventions in Afghanistan and Iraq. “It’s the unknown unknowns that can come back to bite,” as former Defense Secretary Donald Rumsfeld once said in the context of Iraq.

Iran, reeling from five days of Israeli strikes, has vowed retaliation against U.S. bases in the Middle East if attacked, with missiles still in its arsenal despite Israel’s targeting of launchers. Such a response could spiral into escalation, with American casualties pressuring Trump to strike back, potentially targeting Iran’s leadership. “Subcontracting the Fordo job would put the United States in Iran’s sights,” wrote former U.S. ambassador Daniel C. Kurtzer and National Security Council veteran Steven N. Simon in Foreign Affairs on Wednesday, warning of a cycle of retaliation that could drag the U.S. into regime-change efforts—a path few Americans support.

Beyond immediate retaliation, Iran’s cyber capabilities, honed after a U.S.-Israeli cyberattack 15 years ago, and its short-range missiles threaten oil tankers in the Persian Gulf, risking economic disruption. A miscalculation, such as a downed B-2 or a failure to penetrate Fordo, could further complicate the operation, said Rafael Grossi, head of the International Atomic Energy Agency.

The broader strategic risk is that bombing Fordo may not end Iran’s nuclear ambitions. History shows mixed results: Israel’s 1981 strike on Iraq’s Osirak reactor led Saddam Hussein to build a secret nuclear program, undetected until 1991, while Syria’s program was halted by force. “I can’t think of a case where air power alone was sufficient to end a program,” said Gary Samore, a former Obama administration official. If Fordo survives, Iran could quickly restart enrichment, as Samore, now at Brandeis University, noted.

Trump’s hesitation also reflects diplomatic signals from Iran, with an official plane landing in Oman, site of prior nuclear talks, suggesting a desire to negotiate despite Ayatollah Ali Khamenei’s defiance. Trump’s intelligence chief, Tulsi Gabbard, testified months ago that Iran has not decided to build a bomb, a claim Trump disputed without evidence on Wednesday, insisting time is running out.

For now, Trump’s calculus hinges on whether Israel’s strikes on Iran’s Natanz facility and centrifuge workshops suffice to cripple its nuclear program, or if U.S. intervention is worth the gamble. “We haven’t been fighting,” he said in the Oval Office, praising Israel’s efforts but adding, “We’ll see what happens.” With the risks of escalation and the ghosts of past Middle East failures looming, the decision to bomb Fordo remains a perilous crossroads.