Political donors have raised more than $107,000 since September to support the state's only constitutional amendment on the November ballot.
The obscure proposal would amend the Idaho Constitution to allow lawmakers to reject rules created by executive branch agencies, known as a legislative veto.
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A similar proposal was struck down two years ago, so sponsors this year have come back in full force to raise enough money to urge Idahoans to vote yes on HJR 5.
Recent campaign finance reports show that Citizens for HJR 5 has received donations almost exclusively from Republican lawmakers and lobbying groups.
The committee has since contributed more than $56,000 of those funds to the Idaho Republican Party - which supports the amendment.
Gov. C.L. "Butch" Otter recently announced his opposition to the proposal; so has Attorney General Lawrence Wasden.