https://www.catholicleague.org/about-us/
The Catholic League is the nation’s largest Catholic civil rights organization. Founded in 1973 by the late Father Virgil C. Blum, S.J., the Catholic League defends the right of Catholics – lay and clergy alike – to participate in American public life without defamation or discrimination.
They have the full support of many prominent church leaders:
…I appreciate Dr. Donohue and the work done by The Catholic League. I look forward to the day when the work done by the Catholic League is no longer necessary. Sadly, as recent events have proven once again, that day still seems far in the future.”
— Cardinal Timothy Dolan, Archbishop of New York
“The Catholic League has the courage to speak up candidly and forcefully for the Church when circumstances call for fighting the good fight. The League should be on every Catholic’s short list of essential organizations to support.”
— Most Rev. Charles Chaput, O.F.M. Cap.
Archbishop of Philadelphia
“I am privileged to support the Catholic League. The work of the Catholic League is invaluable and its accomplishments over the years are unparalleled.”
— Cardinal Edwin O’Brien
Pro-Grand Master of the Equestrian Order (Knights) of the Holy Sepulchre of Jerusalem
“The Catholic League has done much to ensure that the Church’s positions are presented clearly and fairly. Too often those who do not understand the Church or Her teachings are the interpreters of the doctrines and events in the life of the Church. The work of the League is important in the mission of the Church which must teach the hard truths of the Gospel in season and out of season.”
— Seán Cardinal O’Malley, O.F.M. Cap.
Archbishop of Boston
It's hardly "one guy in his basement." The last official membership count was over 350,000.