President Donald Trump said the United States will begin escorting commercial ships through the Strait of Hormuz starting Monday, a move that signals a direct U.S. military role in keeping one of the world's most critical oil shipping lanes open.

The Strait of Hormuz is the narrow waterway between Iran and Oman through which roughly 20% of global oil supply passes every day. Any sustained disruption there — through mines, drone attacks, or vessel seizures — can spike oil prices within hours and tighten energy markets worldwide.

Diplomacy Stalls, Military Presence Steps Up

Trump also told an Israeli media outlet that Iran's latest peace proposal was "not acceptable," and he declined to rule out a return to armed conflict with Iran. That combination — a rejected peace offer, an open door to military action, and now a naval escort operation — marks a notable hardening in the U.S. posture toward Tehran.

The escort operation effectively means U.S. warships will accompany commercial vessels through the strait, deterring interference. This is not a new concept — the U.S. ran a similar operation, called Operation Earnest Will, during the Iran-Iraq War in the 1980s — but reviving it now sends a strong signal about Washington's read of the threat level.

What This Means for Markets and Energy

Oil traders watch the Strait of Hormuz closely because there is no easy alternative route for much of the Gulf's crude exports. A credible U.S. naval presence could actually calm short-term risk premiums built into oil prices, since it reduces the perceived chance of a sudden blockage. But if the escort operation triggers an Iranian response — harassment, mine-laying, or proxy attacks — the risk calculus flips fast.

The diplomatic breakdown is the sharper concern for energy markets. With Trump calling Iran's offer unacceptable and not ruling out military action, the window for a negotiated deal that could bring more Iranian oil supply back to market appears to be narrowing. That matters for global supply balances, particularly at a time when OPEC+ production decisions are already in focus.

Watch for whether Iran responds to the escort announcement with a statement or action in the strait, and whether the U.S. provides more detail on the scope and duration of the operation. Any Iranian countermove would quickly become the market-moving event.