Tens of thousands of Americans opposed to waging war in Iraq rallied in Washington despite frigid cold on Saturday demanding the White House back down and give UN weapons inspectors a chance.Thousands of others were expected to demonstrate in San Francisco and at smaller protests in Chicago and Tampa, Florida, in what organisers said would be the largest showing of US anti-war sentiment since President George W. Bush started making his case for attacking Baghdad last year.‘‘The path this administration is on is wrong and we object. It is an immoral war they are planning and we must not be silenced,’’ said US actress Jessica Lange, addressing the huge crowd on the National Mall in Washington.Protesters arrived by bus from California, Colorado, Maine, Minnesota and other states and gathered on the Mall on 20 degrees Fahrenheit.‘‘It’s really important for us to show Europe and the rest of the world that we oppose this so they have the courage to say ‘No’,’’ said May Paddock, 60, of Copake, New York. Some held placards reading ‘‘Regime Change Starts at Home’’ and ‘‘Would Jesus Bomb Them?’’.Protesters said the recent deployment of US troops to the Gulf, and widespread speculation that a January 27 report by UN arms inspectors could serve as a trigger for war, had lit a fire under the American peace movement.‘‘Bush is counting on the fact that the American people have been lulled into complacency by prosperity,’’ said Kevin Lynch, from the Catholic Church of St. Joan of Arc in Minneapolis. ‘‘He thinks middle-aged white guys like me are his bedrock supporters, and we’re not.’’ (Reuters)