For all the evidence in the polls that a majority of Americans now oppose the war in Iraq, they have not spilled out into the streets in huge numbers as they did in the late 1960s during the Vietnam War.

There are some obvious explanations. They include the absence of a military draft, many fewer American deaths (nearly 3,700 compared with 55,000 in Vietnam), and no civil rights and cultural revolutions ofthe sort that also churned the public temper in that earlier time.