Wayne LaPierre has been both the most powerful and a controversial figure in the gun rights movement for decades, and his grip on power in the NRA has been amazing. Even though I considered (and still consider) myself a part of the “Neal Knox faction” and desire numerous changes at the NRA, I still support the organization strongly. Failure to support them really is throwing the baby out with the bath water.
So I strongly suggest remaining, renewing, or joining the NRA even if you take issue with some of the leadership and some of what they do. If you want to direct fund specifically to legal defense then check out the NRA’s Civil Rights Defense Fund
Another way to support these types of legal challenges is by contributing to the Second Amendment Foundation. . They even seem to have a way to directly sponsor legal challenges.. I’ve been a SAF supporter almost as long as I’ve been an NRA member (so back to the 80s), and they are another key part of the Pro-2A movement.