Answer:
The phrase "the vast balances may be tilted heavily to our disadvantage" means that the current balance of power in the war may shift in favor of the Axis powers if the United States does not take more advanced positions soon. The prime minister is emphasizing the importance of the United States taking a more active role in the war effort, as this is necessary to prevent a potential loss that could greatly disadvantage the Allies. The balance of power refers to the distribution of military, political, and economic strength between the opposing forces.
Step-by-step explanation: