So what if there are 100,000? There is not, nor will there ever be, a sustainable anti-war movement against Iraq because the college kids are not involved. Most of the demonstrators will be old washed-up hippies and liberal feminists, along with the usual rag-tag assortment of gays, enviros, and anarchists.
I'd suspect Bush will be at Camp David or out of town to avoid the aggravation.
There are useful idiots from every one of Hillary's villages showing up at those things. People used to pay to see these freak shows at the carnivals, but now they get to see them for free, and it's cheap entertainment for the kids.