Yes, because mass protests seem to do well to stop wars. I remember when there were mass protests in the US for the Iraq war and it was over in a month. Remember that time? /s
Mass protests work. But they take time and persistence. It's not the spectacle of the actual mass protest itself, its what they do to create connections and unity between people who previously felt isolated from each other. The most important thing coming out of a protest is not the pictures for the news media, but the "come to this next event" fliers handed out, or mailing lists put together, to continue to build momentum.
Protest was most likely a huge factor in keeping Canada (and probably other potential "allies") out of the war, no matter what Chretien says in retrospect. The federal Liberals in power at the time were on the fence, but the mass protests that week (and leading up to it) were the largest in history and the government clearly saw it would cost them. (But then they turned around and provided backchannel support, and were still involved in Afghanistan, etc. so...)
I suspect getting involved there was also a big factor in the implosion of the UK Labour Party since then...
I marched in the protests that week in Toronto. They were the largest mass street protests -- and probably the most emotional -- I've ever been in. It got pretty heated outside the US embassy, too.
Seems to me the problem in the US with the Iraq war is that Americans are on the whole brought up to be extremely pro-military, "support our troops" at all cost. Lots of ra-ra patriotism stuff that is about the only thing in US society that is not partisan.
Many of the "liberals" I know there still give me shitty excuses why they initially supported what was clearly, to anybody who was thinking a terrible imperialist war. Anybody with half a brain knew it wasn't about "weapons of mass destruction", and people still using that "they lied to us" excuse are being intellectually dishonest. They supported because of nationalism.
And you know what, instead of Russians using this historical example as a "What About?" moment to point fingers at the US -- which accomplishes nothing -- they should be absorbing the actual lesson about the awful things that imperialist nationalism makes people and nations do... and get a spine.
I expected Americans to get a spine then and stop the war, and I expect Russians to do so now. Disappointed both times, so far.
No, the US population was in favor of the war overall, especially at the beginning. I don't know how this compares to the Vietnam war. But the Vietnam war involved conscription, so I'd bet that had more domestic opposition.