[0] https://www.thebalancesmb.com/can-nonprofits-engage-in-polit...
[1] https://www.thebalancesmb.com/how-the-irs-classifies-nonprof...
To oversimplify, 401(c)3 are exempt from taxation and donations to them can be deducted from the donor's income tax liability. As a tradeoff, they cannot participate in political activity.
401(c)4 organizations are permitted to participate in politics as part (but not all) of their activity, and are exempt from taxation, but donors to them may not deduct their donations.
527 organizations exist explicitly for political purposes and are exempt from taxation. However, donors may not deduct their donations, and 527 organizations are subject to more rigorous regulation and reporting requirements due to their almost guaranteed exposure to campaign finance regulation.
The best way to think about it is this: while the IRS permits many types of non-profit organizations to not pay corporate income tax, the ability of donors to deduct donations from their personal income tax is a privilege specifically granted to charities. Charities are a subset of nonprofits which exist for specific purposes, and political advocacy is not one of them.
Subject to state law, it is often possible to incorporate nearly any type of business venture as a nonprofit (even a conventionally for-profit one, such as a retailer). However, the IRS does not grant tax-exempt status to any nonprofit. Only nonprofits of specific types are granted tax-exempt status.
[1] https://www.supremecourt.gov/opinions/17pdf/16-1466_2b3j.pdf
My guess is this slides under the radar, catching a tweet at best. Could give this outfit a few years to spin up, and by then, who's to say?
The current restriction is based on a hastily worded amendment to the tax code from 1954 by one Lyndon Baines Johnson, who later became president when JFK was murdered.
It reduces to a few principles.
1. orgs should use their tax-deductible contributions in support of their stated missions.
2. orgs cannot be set up for "selfish" reasons. Because of the present and historical culture of graft (the buying and selling of political favors) in the US, we basically assume that anybody who promotes a candidate gets something in return.
3. confusion in the US Senate in 1954 about the difference between an org's "primary" mission and other missions.
There's also an undercurrent of church-state separation. By dollar volume, houses of worship are very big recipients of tax-exempt contributions. Politicians fear the influence of people in pulpits, so it's easier to prohibit that.
In May 2017, the current president, Donald Trump, issued an executive order weakening the restrictions on political speech. He did this under pressure from his political party and from the "evangelical" churches who support him.
'Churches' (this is a short reply so I don't have the definition handy) actually get additional benefits on top of a 501(c)3.
Specifically, if they follow certain rules they don't even have to file a proper return. They still have to throw some numbers the way of the IRS, but in addition to not having to file, religious orgs do not have to publish their returns (normal 501s must do so, part of the 'transparency' of their tax break is they must show CEO salaries, salaries of certain top paid employees, and other expenditures).
In many of these situations, the denominational office has sought approval from the IRS, and has an Employer ID number that appears in the nonprofit search. https://apps.irs.gov/app/eos/ This is helpful for getting access to various corporate nonprofit donations. For example, Microsoft Office for nonprofits is very inexpensive.
There are other non-profit organization types that are specifically suited for political action. Labor unions are 501(c)(5) and often very political. But most political organizations are regulated under section 527 of the code.
The reason is simple: different codes require different reporting requirements. The 501 codes are heavily scrutinized by the IRS to make sure they are legitimate charitable causes. 527 orgs are overseen by the FEC to make sure that they obey political campaign financing laws. The reporting requirements for both are different.