"self-igniting cigar or match," 1839 (but presumably older), American English, of unknown origin, perhaps from a misapprehension of the meaning of the first element of locomotive as "self-" + Spanish fuego "fire." During one heated political meeting in N.Y., the lights went out and the delegates used such matches to relight them, thence the name loco-foco entered U.S. political jargon (1837), usually applied to a radical faction of the Democratic Party, but by the Whigs applied to all Democrats.
Examples from the Web for loco-foco
This interrogation lights up Memory, with the suddenness of a 'loco-foco' match.
The regulars were successful, however, at the election; and they and the Whigs dubbed the anti-monopolists the Loco-foco men.
The Whigs had, indeed, been glad enough to have Loco-foco aid and even open alliance at the polls.