Write four to five sentences supporting the inference that the British waited until they were sure the telegram would encourage

The British took their time, ensuring that the telegram would provoke the US into joining the war.

Admiral William Hall was aware that there was increasing anger in America following Germany's declaration on January 31 to renew unrestricted submarine warfare. Realizing that the U.S. was nearing its entry into the conflict, Hall decided to wait until February 24, believing that the Zimmermann telegram would push the U.S. to align with the Allied forces. He presented the telegram without disclosing that the Germans' codes had been broken by the British.

Zimmermann, the German Foreign Secretary, had sent a telegram to Count Von Bernstoff, the German ambassador in Washington, aiming to persuade Mexico to ally with Germany.

Response:

The information in this passage supports the idea that the British waited until they were confident that the telegram would prompt the US to join the war. Hall recognized that "outrage was growing in America over Germany's announcement late in the day of January 31 that the German navy would resume unrestricted submarine warfare." He realized that the US was on the verge of entering the conflict, yet he chose to delay until "February 24, when Hall believed the Zimmermann telegram would tilt the scales toward the U.S.'s involvement with the Allied powers." His decision to wait before revealing the telegram implies he needed assurance of its effectiveness.

Clarification: