Presidents often discount protests, but historians say have an affect.

Byline: Bill Lambrecht

WASHINGTON _ While Vietnam-era war protests raged outside the White House, Richard M. Nixon watched a college football game and told protest organizers they could send him a letter.

Likewise, Lyndon Johnson proclaimed that the anti-war protesters would never alter America's course in Vietnam. He later complained that they were "on the sidelines kicking and crying" while Americans were dying.

Presidents back to Franklin Roosevelt have dismissed anti-war protests, much like George W. Bush did in declaring he wouldn't be swayed by the millions of people around the world who gathered last month to protest a looming American-led invasion of Iraq.

Several million people massed to voice criticism of the United States' policy in the Middle East in 600 cities in 60 countries.

Looking back, historians say it's hard to know if anti-war protests changed foreign policy, even during the turbulent era of the Vietnam War.

Nonetheless, they say, Vietnam taught us how long-running social rifts can have a profound effect on society, leading to diminishing respect for authority and fueling anti-establishment sentiment.