Anyone with a US Employer Identification Number can use WePay to raise money using the Action Network -- organizations, candidates, and more. Anyone who lives in Stripe's areas of operation can do the same using Stripe. (See here for a list.)
No merchant account is required -- once you start a fundraising or ticketed event page you'll be asked to make a free account with WePay or Stripe, our payment processors, to collect your donations.
You can even raise money for multiple groups at the same time, enabling joint fundraisers and bundling.