And, this was opposed by the US delegation to the UN:
http://www.trumanlibrary.org/israel/palestin.htm The UN vote authorizing partition into three zones, Jewish, Arab, and International (the city of Palestine) occurred on November 29, 1947.
May 14, 1948: late morning eastern standard time (late afternoon in Palestine): David Ben-Gurion, Israel's first prime minister, reads a "Declaration of Independence," which proclaims the existence of a Jewish state called Israel beginning on May 15, 1948, at 12:00 midnight Palestine time (6:00 p.m., May 14, 1948,eastern standard time).
May 14, 1948, 6 p.m. eastern standard time (12:00 midnight in Palestine): The British mandate for Palestine expires, and the state of Israel comes into being.
May 14, 1948, 6:11 p.m. eastern standard time: The United States recognizes Israel on a de facto basis. The White House issues the following statement: "This Government has been informed that a Jewish state has been proclaimed in Palestine, and recognition has been requested by the provisional government thereof. The United States recognizes the provisional government as the de facto authority of the State of Israel." To see a color copy of this document click here.
May 14, 1948, shortly after 6:11 p.m. eastern standard time: United States representative to the United Nations Warren Austin leaves his office at the United Nations and goes home. Secretary of State Marshall sends a State Department official to the United Nations to prevent the entire United States delegation from resigning.
This is all about putting the brakes on diplomatic pressure the US is now applying. There is widespread international support for recognizing Palestine, particularly within the EU. Mitchell's telling Netanyahu that if Israel continues to be unwilling to negotiate the terms of partition with the 1968 borders as a framework, the rest of the world is going to go ahead and vote in the UN to recognize the establishment of Palestine as a full voting Member along those lines.
This House vote undermines the Administration's negotiating strategy.