In investing, we want to diversify our holdings to ensure that we don't lose too much money if any one asset's value crashes. More technically, we want to minimize the overall risk of our portfolio by investing in a basket of uncorrelated assets, which can be encapsulated in an index fund. Likewise, if a donor is interested in supporting a bunch of EA-aligned political candidates, wouldn't it be better to donate to a political action committee (PAC) that supports all of them, such as Guarding Against Pandemics?
Note: Under U.S. election law, individuals and corporations can contribute up to $5000 to a PAC, and PACs can donate their proceeds to political campaigns (up to $2600-5000 per candidate). Super PACs can receive unlimited amounts of money from donors but cannot donate their proceeds directly to candidates.