Why a foreign-yard clause would sink the Washington treaty

What if the Washington Naval Treaty required each signatory to build part of its new fleet in foreign shipyards?

The powers would refuse to sign because naval construction was a core domestic industrial and strategic capability.

The major powers simply would not sign such a clause. Naval construction sustained domestic yards, skilled labor, strategic capacity, and political spending, so outsourcing was not a neutral accounting choice. Britain would not accept building its treaty ships in American yards, nor would the United States accept the reverse arrangement. Because universal participation was essential to limitation, the added requirement would collapse the negotiations rather than redistribute contracts.