BOISE, Idaho — The state’s top Senate leaders say Gov. C.L. “Butch” Otter was wrong to question the constitutionality of their legislative process while passing a contentious bill that would have repealed the sales tax on groceries.

The vetoed proposal is currently at the center of a high-profile lawsuit, involving 30 GOP state lawmakers against Otter and Secretary of State Lawerence Denney. Legislators argue that Otter took too long to veto the bill. They have petitioned the Idaho Supreme Court to weigh in on the issue to force the repeal of taxation on food.

Meanwhile, Otter argues that the bill may have never been legal in the first place because it did not originate in the correct legislative chamber.

Now the Senate’s top heads — which includes both Republican and Democratic leaders — want to get involved in the lawsuit, but only to defend their actions on how they passed the bill — not to argue whether Otter messed up the veto deadline.

“Governor Otter’s argument challenging the constitutionality of HB67 directly implicates the authority of the Senate and calls into question the proper interpretation and application of … the Idaho Constitution,” attorneys for the Senate’s leadership wrote to the court on Friday.

During the legislative session, House lawmakers passed a bill slashing individual and corporate income tax rates. When it got to the Senate floor, however, a small group of conservative lawmakers hijacked the bill and successfully convinced members to completely transform the proposal into a grocery tax repeal bill. Because the bill was amended, it was sent back to the House — where it was once again approved.

Otter then vetoed the bill 11 days after the session adjourned.

According to the Republican governor, lawmakers were wrong to send him the grocery tax repeal bill because the original language of the legislation did not start in the House. The Idaho Constitution requires revenue bills to start in the House.

Senate lawmakers counter that HB 67 did start in the House.

“The determination Governor Otter seeks regarding the interpretation and application of Article III (of the Idaho Constitution) would potentially eliminate the Senate leadership’s legislative authority to amend ‘revenue raising bills’ and corresponding effect on the legislative process would be widespread and immediate,” the senators wrote.