What happens if the conflict between Israel and Iran escalates and widens? Here are some possible"worst" scenarios, according to the BBC's analysis...

FIRST SCENARIO: USA IS DRAGGED INTO WAR

Although the United States denies this, Iran clearly believes that U.S. forces approve of Israel's attacks and provide at least tacit support.

Iran could attack US targets in the Middle East, including special forces camps in Iraq, military bases in the Gulf and diplomatic missions in the region. Hamas and Hezbollah may be"weakened," experts say, but Iran's militia backers in Iraq remain armed and intact.

The US had anticipated such attacks and withdrew some of its personnel, and in public statements it has explicitly warned Iran of the consequences of any attack on American targets.

From Iran's ballistic missile attacks on Israel on Saturday midnight. AP

Donald Trump may be forced to act. Israeli Prime Minister Benjamin Netanyahu has long been accused of wanting to draw the United States into war against Iran.

Military analysts say only the United States has the bombers and bunker-busting bombs capable of penetrating Iran's deepest-lying nuclear facilities, particularly Fordow.

Trump promised his MAGA voters that he would not start a new"endless war" in the Middle East. But many Republicans, by the same token, support the view that it is time to change both the Israeli government and now the regime in Tehran.

But if the United States were to become an active belligerent, this would be a major escalation and could have long-term, devastating consequences.

If Iran cannot damage Israel's well-defended military and other targets, it could direct its missile attacks at softer targets in the Gulf states, which it believes have supported its enemies for years.

There are many potential targets in the region for energy and infrastructure. Iran was held responsible for the attacks on oil fields in Saudi Arabia in 2019 and the targeting of the UAE by Yemen's Houthis in 2022.

Since then, a certain understanding has been reached between Iran and some countries in the region.

But these countries host US air bases. Some of them helped"secretly" defend Israel from Iranian missiles last year.

If the Gulf were attacked, it could demand that American warplanes be deployed to defend itself and Israel.

THIRD SCENARIO: WHAT IF IRAN’S NUCLEAR CAPACITY CANNOT BE DESTROYED?

The BBC outlined this scenario by asking,"What if Israel's attack fails? What if Iran's nuclear facilities are too deep, too well protected? What if 400 kilograms of 60 percent enriched uranium, almost weapons grade, enough to make about ten bombs, cannot be destroyed?"

This material is thought to be hidden in secret mines. Israel may have killed some nuclear scientists, but no bomb can destroy Iran's knowledge and expertise.

What if this attack convinces the Iranian leadership that the only way to prevent further attacks is to achieve nuclear weapons capability as quickly as possible?

What if the new military leaders at the table are more headstrong and less cautious than their deceased predecessors?

In that case, Israel could be forced to launch new attacks, and the region could be trapped in a perpetual cycle of attack and counterattack — a strategy Israelis call, in a grim phrase, “mowing the lawn.”

FOURTH SCENARIO: GLOBAL ECONOMIC SHOCK

Oil prices are already soaring.  What if Iran tries to close the Strait of Hormuz to further restrict oil shipments? What if, on the other side of the Arabian Peninsula, Yemen’s Houthis step up their attacks on shipping in the Red Sea? The group is Iran’s last remaining proxy force, known for its past aggression and unpredictability.

Many countries around the world are already experiencing a cost-of-living crisis. Rising oil prices will further exacerbate the effects of Trump’s tariff war, which is already putting serious pressure on the global economic system.

"It's important to remember that the person who would benefit most from rising oil prices is Russian President Vladimir Putin. It would generate billions of dollars in new revenue for the Kremlin to finance its war in Ukraine," the BBC said.

FIFTH SCENARIO: IRANIAN REGIME COLLAPSES, A VACUUM FORMS

What if Israel succeeds in its long-term goal of overthrowing the Islamic revolutionary regime in Iran?

Netanyahu says his primary goal is to destroy Iran's nuclear capabilities, but he also made clear yesterday that his broader goal is regime change.

He said he was addressing"the proud people of Iran" and claimed that the attack "opens their path to freedom from their evil and oppressive regime".

"The overthrow of the Iranian government may seem appealing to some people in the region, particularly some Israelis. But what kind of vacuum would that create? What unforeseen consequences would that have? What would a possible civil war in Iran look like?" the BBC commented.

"Many people still remember what happened after the collapse of the central governments in Iraq and Libya. So how this conflict will progress in the coming days is of great importance."

How and how forcefully will Iran respond? And to what extent will the United States be able to rein in Israel? The answers to these two questions will largely determine how the process unfolds.