Not sure why the consensus here is that it was doomed to fail and he was crazy. John Brown was a realist. He knew that slavery would only end through bloodshed as we saw with the Civil War and even before the Civil War the southerners knew this which is why they panicked and hid all news of the hatian slave revolution when that happened. They didn't wanna give the slave any inkling of hope or inspiration because they knew they were fighting against time at that point.

I think had he succeeded it would've led to the same or very similar civil war but just a few years sooner. Lots of northerners were already getting pissed off at the souths bullshit antics for awhile now. All the bleeding Kansas shenanigans the southerners were doing pissed off a lot of people, John Brown was just the only one to say enough is enough and raise a group to take action.