Has to happen in a single day. Similar to https://en.wikipedia.org/wiki/2017_Women's_March which reported between 3,267,134 and 5,246,670 total participants in the US. I'll resolve based on a consensus of credible media sources and/or wikipedia.
Update 2025-02-01 (PST) (AI summary of creator comment): Anti-Trump Protest Definition Clarification
A protest does not need to be solely a demonstration against the person of Donald Trump. It is sufficient if it is motivated by his policy positions, rhetoric, or their perceived impact.
For example, the Women's March qualifies as an anti-Trump protest because it was prompted by Trump’s policy positions and rhetoric.
1,000@EricMoyer yes. per wikipedia:
> The Women's March[11][12][13][a] was a worldwide protest on January 21, 2017, the day after the first inauguration of Donald Trump as the president of the United States. It was prompted by Trump's policy positions and rhetoric, which were and are seen as misogynistic and representative as a threat to the rights of women.