As the main force of the Special Military Operation Against the US, Britain, France, and Spain would each dispatch at least 200,000 troops to fight the United States, for a combined force of roughly 600,000.
Including the troops sent by Italy and other League of Nations countries, the total number of International Allied Forces in this Special Military Operation Against the US would reach one million.
A force of one million men was clearly enough to deal with the United States in the short term. Although American industry and economy were at the level of a superpower, in terms of military strength—especially army strength—the United States could not even compare with the medium Great Powers of Europe.
On one hand, this was because the United States pursued the Splendid Isolation policy and rarely took part in wars on the European continent. On the other hand, the United States had no particularly powerful enemies around it, so it had no need for an overly strong army to defend its homeland.
The armies of the other countries would still need time to assemble, but Britain, France, and Spain could not afford to wait that long.
Compared with the other countries, Britain, France, and Spain possessed stronger organizational capabilities and could mobilize and transport their armies to the United States in a shorter time.
The United States was at its weakest right now. Striking the US Government by surprise under such circumstances could plunge the country into widespread chaos, leaving the US Government powerless to retaliate.
If the US Government were given more than a month to prepare, then by the time the International Allied Forces arrived in the United States, the American army would already be waiting in full battle formation.
Even if the American army had little actual combat capability, those