An invisible primary is said to begin when a candidate formally announces their plans to run for office. The invisible primary comes to a close when the actual primary season begins.
The invisible primary is a testing-ground for candidates and their advance teams. It’s an opportunity to find out how much support they can gather before the real primary is held. In fact, the invisible primary can often make or break candidates – candidates who don’t get enough shows of support during the invisible primary often end up bowing out of the race, sometimes before the primary season even begins.
A key example of that in the 2020 presidential race would be Sen. Cory Booker. The New Jersey senator dropped out of the race for the Democratic presidential nomination on January 13, 2020, almost a month ahead of the Iowa caucus. Booker had been struggling in the polls for some time; he also wasn’t able to raise enough money to keep his campaign going and to maintain his reputation as a serious candidate.
The invisible primary is often referred to as the “money primary.” That’s because pundits and party bosses are closely watching to see how effectively each candidate can fundraise.
Critics of the invisible primary say that effectively, it forces candidates to curry favor with the most wealthy and powerful Americans. Big donors, as well as well-connected fundraisers (“bundlers”) have a disproportionate role in picking candidates.
On the right, wealthy donors like the Koch brothers, or Sheldon Adelson, have traditionally held a great deal of sway.
On the left, prominent fundraisers include George Soros and the Facebook founder Denis Moskowitz.
In recent years, more and more presidential candidates are, themselves, extremely wealthy men who have the capacity to fund their own campaigns. This has arguably changed the whole nature of the invisible primary, and may have lessened the power traditionally held by wealthy donors and fundraisers.