The ACLU’s old position on restrictions on campaign contributions (as quoted in a WSJ op-ed) was:
Limitations on contributions or expenditures made by individuals or organizations for the purpose of advocating causes or candidates in the public forum impinge directly on freedom of speech and association. Their implementation poses serious dangers to the First Amendment. They should be opposed in candidate as well as referenda elections.
That position was right. “Campaign contributions” is simply like-minded people pooling their money to fund their speech. Limits on campaign contributions are no more or less than a limit on free association and speech.
That position put the ACLU at odds with the bulk of the liberal establishment, who want to limit free speech. In fact, liberal politicians tried to cap expenditures as well as contributions (that is, the actual speech, and not just the free association to fund speech) but was blocked by the Supreme Court.
That probably made for awkward moments at dinner parties. Anyway, whatever the reason, the ACLU Board of Directors has voted to reverse its position. The ACLU is now officially okay with limits on free speech.