Democrats and former officials have accused the department of pursuing a political goal in the guise of a legal one: to publicize a scheme, sordid but not illegal under state law, damaging to Democrats.
The Justice Department issued subpoenas, a House oversight committee sought interviews and the state opened its own inquiry into a Democratic plan to recruit a spoiler into a Senate race.
Republican anger grew on Thursday over a Democratic effort to stack Alaskaβs Senate ballot with candidates to siphon votes from the G.O.P. incumbent.