Predicting "When will Trump end the war"? These are the five key points.

The Iran war has become the strongest geopolitical shock to the global energy market since the Gulf War in 1990.

Since the outbreak of the Iran war on February 26, 2026, Brent crude oil has surged by 44% in just 25 days, the wholesale price of gasoline in the U.S. (Rbob) has risen by 48%, the price of diesel in the U.S. has increased by 51%, and the price of diesel in Europe has gone up by 58%.

Barclays Capital’s latest research report warns that when the war ends will directly determine whether crude oil prices return to the baseline scenario of $85 per barrel or break through $110 per barrel. For investors, five key catalytic factors—military objective progress, congressional funding battles, U.S. military casualty figures, gasoline retail prices, and Trump’s personal judgment—are critical variables for pricing in the current energy market.

Barclays believes that oil price trends will diverge at three key time points: if the Strait of Hormuz returns to normal passage in early April, Barclays maintains the baseline forecast of an average Brent crude oil price of $85 per barrel in 2026; if delayed until late April, the average price may be re-evaluated to around $98 per barrel; if delayed until the end of May, the average price could reach $111 per barrel. With each day of delay, the cumulative inventory gap is transmitted backward due to a snowball effect, raising the price center.

Five Key Factors: Core Variables Determining the War’s Outcome

Barclays public policy analyst Michael McLean has identified five potential catalytic factors that could end the Iran war:

Key Point 1: Achievement of Military Objectives

According to CCTV News, the U.S. has previously outlined three objectives regarding Iran: to destroy Iran’s ballistic missile and drone capabilities; to strike Iran’s navy to maintain passage through the Strait of Hormuz; and to destroy Iran’s military and industrial infrastructure to render it incapable of foreign attacks for years. Notably, regime change or Iran’s nuclear program is not included in these objectives.

President Trump estimated at the beginning of the war that operations would last “four to five weeks.” The war is currently in its third week, and according to the White House, it may be at a midpoint.

However, in terms of the number of targets, there has been no apparent point of action contraction from the U.S. Central Command, with additional forces still being deployed. Although the frequency of Iran’s ballistic missile and drone attacks on the UAE, Kuwait, Saudi Arabia, and Bahrain has significantly decreased, it has not completely stopped, indicating that Iran still retains some offensive capability. Barclays believes that until relevant indicators are further reduced, it cannot be determined that military objectives have been achieved.

Key Point 2: Congressional Constraints—The War Powers Act Creates a Hard Deadline of May 31

The War Powers Act stipulates that the President must obtain congressional authorization (AUMF) within 60 days after deploying armed forces and submitting a report to Congress, with an additional 30-day extension possible; military operations must be forcibly terminated after 90 days. Trump submitted his report on March 2, making the hard deadline for the 90 days May 31.

AUMF requires 60 votes in the Senate to pass, while the Republican Party currently holds only 53 seats. The Democrats have already passed two resolutions opposing this, making it highly unlikely for AUMF to be approved; May 31 is a hard institutional boundary for the end of the war.

The economic cost of the war is also accumulating rapidly: about $11 to $12 billion was spent in the first week, and the current daily operating cost has decreased to about $500 million, with total estimated expenditures to date around $21 billion.

In comparison, the nominal cost of the Iraq War over 13 years was $815 billion; the total discretionary defense spending for the fiscal year 2026 is $839 billion. Additionally, “One Big Beautiful Bill” has allocated $150 billion to the Department of Defense, currently providing some funding buffer.

Key Point 3: Rising U.S. Military Casualties Will Further Erode Public Support

Barclays states that the support for this war within the U.S. is weak and shows clear partisan division.

As of March 22, the average support rate according to RealClearPolitics polls was only 41%, with an opposition rate of 49%. President Trump’s overall approval rating has slightly decreased from 43% to 42%, marking the lowest record of his second term (the lowest in his first term was 37% in December 2017).

Currently, 13 U.S. soldiers have been killed.

Historical experience shows that wars typically bring about a “rally-around-the-flag” effect, where presidential approval ratings receive a temporary boost, but Trump has not experienced this effect. The general rule is that the longer the war lasts, the higher the casualties, and the more pessimistic the public is about the prospects for victory, the stronger the anti-war sentiment becomes.

Key Point 4: Gasoline Prices Touch the “Political Red Line”—$5/Gallon is the Key Threshold

In July 2022, during Biden’s presidency, the national average gasoline price peaked at $5.01 per gallon.

For the Republican Party, not exceeding this “Biden peak” is a psychological political line, corresponding to a WTI oil price of about $120 per barrel, which is more than 20% higher than current oil prices.

Currently, Republican officials remain relatively optimistic, believing that even if oil prices are under short-term pressure, there is enough time for prices to drop back before Labor Day (when investors really begin to pay attention before the midterm elections) as the war ends. The administration has also taken a series of measures to try to alleviate pressure on oil prices, including releasing strategic reserves and waiving related sanctions.

Key Point 5: Trump’s “Declare Victory” Shift

Barclays believes that regardless of the actual progress on the battlefield, there remains a possibility that Trump may declare victory and end the war at some point. When previously asked how to determine when the war would end, Trump’s answer was intriguing—“When I feel it in my bones.”

Barclays clearly points out that the timing of this catalytic factor is almost completely unpredictable.

In communications with clients, a mainstream analogy suggests that Trump’s previous policy shift after “Liberation Day” (the announcement of tariffs on April 2, 2025) has conditioned investors to reflexively think that a market crash could drive Trump to pivot.

However, Barclays believes that the current market response is not “panicked” enough: the S&P 500 index fell about 12% after Liberation Day, while it has only dropped about 5% since the start of this war; the 10-year U.S. Treasury yield jumped 60 basis points after Liberation Day, but has only risen about 40 basis points this time; the investment-grade credit spread widened by 26 basis points after Liberation Day, while this time the peak only widened by 9 basis points. More importantly, suspending a tariff executive order is far easier than ending a real war.

Significant Upside Risk for Oil Prices

Barclays’ core judgment is that the current rise in oil prices is not a speculative bubble, but a reflection of real supply-demand imbalances.

Before the war, Brent crude oil was undervalued by about 19% relative to the OECD inventory levels’ implied historical fair value and by about 15% relative to the substitute cost model; the net speculative long positions in Brent and WTI were at the second percentile of historical lows since 2014 by the end of 2025.

The dynamic evolution of the five catalytic factors—military objective progress, congressional funding battles, U.S. military casualty figures, gasoline retail prices, and Trump’s personal judgment—will be the most important high-frequency tracking dimension for judging the direction of the energy market going forward. Barclays clearly points out that under uncertainty, the risk of the 2026 Brent crude oil forecast of $85 per barrel is tilted upward.