Julián Castro says his 2020 campaign needs to raise $800,000 by Oct. 31

Julián Castro said Monday that his 2020 presidential campaign must raise $800,000 by Oct. 31 — or it "will be silenced for good."

Why it matters: Castro's existential ultimatum follows a similar plea last month from Cory Booker, who pulled in $1.7 million in just over a week to stay in the race. If Castro is successful, other lower-tier Democrats may attempt to replicate their strategies to pull in quick bursts of fundraising to try to make waves in the crowded primary field.

Go deeper: 2020 candidates' Q3 fundraising hauls