A term used as camouflage by the timid and cowardly to hide their true political affiliation. Statistically, independents vote more reliably for parties they "lean towards" than actual party members. To call oneself an independent is to scream, "please don't hate me".
That guy calls himself a "democratic-leaning" independent, but he votes for Democrats every single time. Like we can't tell what he truly is; he's an idiot!