Senator says US-Israel relations at lowest ebb

Senator Charles Percy in a television interview predicted that Israel's Lebanese incursion could turn out to be its ''Vietnam'' and said relations between the United States and Israel were at their lowest ebb in 25 years.

Mr. Percy, chairman of the Senate Foreign Relations Committee, said opposition to Israel's actions is rising both in Congress and the American hinterland. Percy said the Begin government had in Lebanon broken a promise to the US that it would not undertake major Middle East moves affecting American interests without informing Washington first.