Trump last week vetoed a bipartisan resolution directing the White House to end US involvement in the Saudi-led war in Yemen. The House passed the resolution by a 274-175 vote in early April, less than a month after it was approved by the Senate 54-46. US Congress would need two-thirds vote in both the House and the Senate to override Trump’s veto.
"I am writing to ask for your support for over-riding that veto," Sanders said in the letter on Monday. "Let us agree that it is imperative that Congress reaffirm the power given to us by the Constitution over matters of war, one of the most serious duties we have as members of Congress."
Sanders said US logistical and intelligence support as well as aerial refueling of Saudi war planes clearly meets the definition of introducing the United States into conflict, as outlined in the War Powers Act of 1973.
Article I, Section 8 of the Constitution states clearly that Congress shall have the power to declare war, Sanders noted.
The Saudi-led coalition has been carrying out airstrikes against the Houthis in Yemen at the request of President Abd Rabbuh Mansur Hadi since 2015.
The intense fighting has resulted in one of the world's most acute humanitarian crises, with about 22 million people in Yemen currently in need of assistance, according to UN figures.