Missouri Attorney General Chris Koster has sided with Gov. Jay Nixon in determining that a vetoed tax cut bill could have applied retroactively.
At issue is a provision triggering an automatic one-half of a percent reduction in Missouri's income tax rates if the federal government makes it easier for states to collect taxes on online sales.
Koster released an analysis Thursday concluding that the tax-rate reduction could apply retroactively, entitling people to refunds on three previous years of taxes. That backs Nixon's assertion but is at odds with an analysis by the legislative research office.
Koster examined the issue at the request of House Speaker Tim Jones.
Jones wants to override Nixon's veto of the tax cut. Jones dismissed Koster's analysis as a "partisan opinion" ''parroting the governor's talking points."