However, the ACLU played a pivotal role in challenging many of the infringements to civil liberties that occurred during the Red Scare era. The Red Scare, characterised by heightened fear of communist influence and paranoia over potential Soviet spies within the United States, led to significant repression of freedom of speech, association, and other fundamental rights.
In response to these intrusions on constitutional rights, the ACLU vigorously defended individuals targeted by government investigations, loyalty boards, and congressional probes into alleged communist affiliations. The organisation challenged the lack of due process in many proceedings, advocated for the recognition of the Sixth Amendment right to counsel, and opposed loyalty tests that required public employees to renounce any associations with suspected communist activities.
The advocacy of the ACLU and other civil rights groups was crucial in eventually bringing an end to the most egregious excesses of the Red Scare and contributed to shaping a deeper understanding of the value of civil liberties protections amidst societal crises.