What are two things needed to run a big national campaign?

Answer 1

Whether running for a national office (President) or making a national policy push (i.e pushing a specific agenda, independent of any individual election), there are really two things needed:

1. A large organization - the ability to get things done in the thousands of local jurisdictions that make up the entire country. In the case of a candidate, this means getting enough petition signatures to get the candidate on the election ballot, and organize local fundraisers and political rallies to get the local voters enthused about the candidate. In the case of a national policy push, the staffing levels are lower, since the majority of work is media-related. However, if trying to coordinate state or lower ballot initiatives, then the same organizational challenges that a candidate faces occur. The candidate or policy organization realistically needs hundreds of members, and most big campaigns have several thousand volunteers in addition to a couple hundred paid staffers.
2. Lots, and Lots of money. Media buys (newspaper, radio, and TV) cost enormous amounts of cash, and traveling costs for the candidate (or the frontman promoters of a cause) can run into the millions easily. Costs to pay for rallies, placards, banners, and printed media are also huge. Realistically, $100 million is a bare minimum to run a national political campaign these days, and, for a Presidential candidate, $500 million seems to be about the minimum to have a viable chance at winning.