Harding isn't quite as strong a candidate as Coolidge would be, seeing as there's still a little mistrust out of teapot dome and the like. But it's not fatal, as Harding is generally seen as having exercised bad judgement in his trust of others rather than being corrupt himself, and economic times are good.
McAdoo's progressive stances bite some into La Folette's strength. The selection of Smith as his running mate is a double-edged sword: It brings in Catholics and other traditional Democratic voters in the North who are unsure about McAdoo and the party in general post-Wilson, but diminishes support in the South among the more xenophobic and elsewhere who are otherwise supporters of McAdoo. Still McAdoo does not have any trouble carrying the Solid South . . . but the Republicans are too strong in the rest of the country to be beaten.
Harding/Coolidge 51% 353McAdoo/Smith 35% 165La Follette/Wheeler 13% 13