Federal court records show just 129 people have been charged under the U.S. "voting by aliens" law since 1996, far below President Donald Trump's claims of rampant noncitizen voting.
Most of those cases stemmed from misunderstandings or miscommunication rather than organized fraud, according to the Reuters analysis of prosecutions.
Trump has argued noncitizens are voting as part of a conspiracy to weaken Republican power, but the report says evidence supporting that allegation remains sparse.
The administration has still intensified efforts to police noncitizen voting, a push election experts and critics warn could suppress turnout and disenfranchise eligible voters.