Occasional media hype notwithstanding, I have yet to encounter any serious objections to putting Harriet Tubman on the $20 bill; I certainly don’t have any. I have seen some studied indifference, though:
This makes me no never mind. I rarely use cash any more and I can’t remember the last time I had a twenty in my wallet. If the government wanted an African-American in that slot, I would have opted for Martin Luther King or even Jackie Robinson. Say what you want, both men changed this country for the better.
Do you want to keep Andrew Jackson around? Put him on the half-dollar coin which the US still insists on minting for some reason; the only reason Kennedy’s on there is because he got his brains blown out in Dallas back in ’63.
The half-dollar exists mostly, I believe, as a unit of measure for hail: it neatly splits the difference between quarter-size hail and ping-pong ball-size hail. I haven’t actually seen a half-dollar actually being used as money, such as it is, in years.