There are no tax breaks for 501(c)(4) groups. Contributions to these organizations are not tax deductible, and the tax liability of the 501(c)(4)s wouldn’t change if they were reclassified as political committees.
This is not about taxes, so what is it really about?
Disclosure. In cases involving unions, the NAACP and other civil-rights organizations in the 1940s, ’50s and ’60s, the Supreme Court made clear that people have a right to engage in anonymous political activity.
In the 1976 Buckley v. Valeo case, however, the court carved out a narrow exception, allowing the government to compel the disclosure of information about donors to groups controlled by political candidates and parties, or that have the primary purpose of engaging in political campaigns. But the court also defined political activity narrowly, to include only the express advocacy for the election or defeat of a candidate. The ruling specifically did not include the discussion of candidates and issues as a political-campaign activity.