Would HMS Incomparable force an Anglo-American naval race?

Would building HMS Incomparable have forced the United States to match Britain or accept second-power status?

Not automatically; American prestige favored matching Britain, but Senate funding and the negotiated balance among cruiser categories would still determine the actual fleet.

The United States was unlikely to accept the label of second naval power, but matching a spectacular British ship would still require congressional funding. The Senate's reluctance to spend on the navy could matter more than rhetoric about prestige. Under the later treaty system, the United States accepted slightly less total cruiser tonnage than Britain while receiving more heavy cruisers. Britain balanced that category with a larger number of light cruisers. Naval parity therefore depended on budgets and force mix as much as on any one enormous battlecruiser.