The Rebbe, following the Rebbeim before him, was firmly against drinking mashkeh except at times of joy, and even then only in a limited measure. Where there is any concern of becoming intoxicated, even a small amount is forbidden, and this applies all the more at public farbrengens.
The Rebbe gives two reasons why earlier customs of drinking freely no longer apply. First, Anash now have ready access to maamarim and sichos with explanation, so they can inspire others without much mashkeh. Second, the mission of spreading the wellsprings outward is directly harmed by excessive drinking. He also rejects the claim that mashkeh is needed in order to say words of inspiration: the harm is certain while the benefit is doubtful.
Key letters: Igros Kodesh 1927 (8 Kislev 5713), 5861 (20 Cheshvan 5718), 7408 (22 Menachem Av 5720), 8552 (1 Kislev 5723).