Does protesting in the streets ever work?

Does doing mass protest ever work?

On local issues I can see it working. Ie protesting against your local council or your workplace.

But on huge issue like war. Vietnam war you have demostrations after demonstations. Did that stop the war? The US only stopped when they lost the war. The iraq war protest didn't stop the war. In UK the mass protest against the ban on fox hunting didnt change anything.

Live 8 is a mass demostration by itself against the G8 summit. Does it do anything?

It has to be on an absolutely massive scale to work. That's why the Iraq war ones don't do anything; they aren't big enough and most of the people in them are tinfoil retards anyway.

What you need are sustained, coherent nonviolent protests on a big scale, just like during the civil rights era. These work because they are a political force that politicians can;t dismiss out of hand; when they become violent, politicians can write off the protestors as whackjobs to the rest of the population, and it hurts the movement.