The White House today issued a Statement by President Biden (full text) extending warm wishes from him and the First Lady to Buddhists in the United States and around the world celebrating Vesak. the Statement says in part:
As we honor the birth, passing, and enlightenment of Buddha, we recognize the American Buddhists who contribute so much to our communities and our country. For over 2,500 years, those who adhere to the Buddha’s teachings have enriched and strengthened this world we share. Vesak is a time to reflect on the Buddha’s teachings, including the need to work for peace and justice, and cultivate humility and compassion as we work together towards a brighter future.
Secretary of State Anthony Blinken also issued a statement (full text) recognizing the day.
A posting on the United Nations website explains the holiday in more detail, saying in part:
"Vesak", the Day of the Full Moon in the month of May, is the most sacred day to millions of Buddhists around the world. It was on the Day of Vesak two and a half millennia ago, in the year 623 B.C., that the Buddha was born. It was also on the Day of Vesak that the Buddha attained enlightenment, and it was on the Day of Vesak that the Buddha in his eightieth year passed away.