The central scenario: Enterprise, Hornet and Yorktown are lost while most Japanese fleet carriers and effective air groups survive. This is a stated assumption, not a forecast with an assigned probability.
The real battle cost the United States Yorktown. Losing all three therefore adds Enterprise and Hornet to the actual American loss while also changing the Japanese result. Keeping that baseline explicit avoids counting Yorktown twice. M18
Three different victories
If the Americans withdrew after losing one or two carriers while Japan also suffered serious losses, Japan would have a better opportunity to continue the operation. Its own damage and depleted air groups would constrain that opportunity.
If all three American carriers were lost and most Japanese striking power survived, the immediate shift would be much sharper. Mobile American air cover would become scarce while Japan retained a concentrated carrier force.
If Japan also captured Midway and sustained a useful base there, the United States would lose a forward reconnaissance and staging position. That would require additional achievements after victory at sea: landing, overcoming the defenders, repairs, equipment and supply.
Why losing the carriers mattered
Nimitz’s operational plan warned against committing to an engagement likely to cause heavy losses in American carriers and cruisers. Preserving scarce fighting power was part of the task, alongside defending Midway and damaging the enemy. M26
Carriers provided moving reconnaissance, fighter cover, strike aircraft and the organisation to keep aircraft operating with a fleet. Shore aircraft could protect particular places, but could not provide the same moving cover for a distant convoy or amphibious force.
What would remain?
The Gray Book’s 6 June entry records Saratoga’s arrival and fuelling, with departure to rendezvous planned for the following morning. Reinforcement was close, but absent from the decisive carrier engagement. One flight deck would not replace three. M19
Wasp was transferring from the Atlantic and still needed transit and preparation time. Her ship history records departure from Norfolk on 6 June, passage through Panama on 10 June and arrival at San Diego on 19 June. She cannot be placed at Midway on 4 June as an immediately usable reserve. M29
These historical movements are a starting point for the assessment. A defeat could have changed subsequent orders.
A harder offensive, not an automatic end to the war
With fewer carriers, protecting bases, covering essential shipping and preparing an offensive would compete for the same scarce force. A delayed, smaller or differently supported offensive is a reasonable possibility. No fixed delay is assigned.
The Japanese would still need serviceable aircraft, trained personnel, fuel, ammunition and support. Victory would expand their options without making all operations possible at once.
Neither the fall of Hawaii nor an American decision to make peace follows automatically. Defeating a carrier force, taking an island and sustaining a wider offensive are different achievements. The scenario should expose those conditions rather than conceal them.