In 1882, Weller upset sitting Republican congressman Thomas Updegraff in the race to represent Iowa's 4th congressional district in Congress.

[3] Weller benefited from a nationwide wave of anti-Republican sentiment that would cost the party control of the U.S. House and one-fifth of its seats in that chamber.

[4] However, no other Greenback candidate won a seat in the Forty-eighth Congress,[5] and Weller owed his election to support from the Democrats in his district, who had endorsed his candidacy.

"[9] In fact, others claimed that it came from his long string of failures in winning public office, and the nickname stuck because, for members of the mainstream parties, it left the impression of Weller as a Luddite in a world of economic progress, or a doomsayer in a time of general prosperity.

He limited his objection to those banks' power to issue currency of their own, and this, too, was a position which many Democrats had long shared, and which found favor among prominent economists far from the radical camp, including Professor William Graham Sumner at Yale University.

[12] Weller sought re-election in 1884 and had faithful support from Democrats, and though he was defeated by Republican nominee William E. Fuller, failed by barely two hundred votes.

A "middle of the roader," as opponents of fusion were called, he led an increasingly forlorn hope in a state where Populism had never done all that well.