BOISE — Two lawmakers from eastern Idaho threatened Wednesday to take legal action against Gov. Butch Otter after accusing him of missing the deadline to veto legislation that would have repealed the 6 percent sales tax on groceries.

The Republican governor nixed the proposal late Tuesday evening. Otter has previously said he had 10 days to make a decision starting when the bill was delivered to his office, two days after the state legislative session adjourned.

However, GOP Reps. Ron Nate and Bryan Zollinger disagree. The Idaho Falls representatives argue that the Idaho Constitution says the 10-day deadline starts immediately after the Legislature adjourns, not when the governor receives the bill.

Lawmakers went home for the year on March 29. Otter received the grocery tax repeal bill, one of the most contentious proposals passed by the Legislature this year, on March 31.

“We are prepared to take all legal means necessary,” Nate told reporters.

The veto of the tax repeal has already been validated by the secretary of state’s office, said Chief Deputy Tim Hurst.

Hurst said Nate’s and Zollinger’s criticism has already been settled by the Idaho Supreme Court. In 1978, justices issued a split 3-2 decision ruling that the veto deadline period does not start until bills arrive on the governor’s desk regardless of when the Legislature adjourns.

“We conclude that the governor has 10 full days from the date of presentment in which to consider bills presented to him after adjournment of the Idaho Legislature,” the ruling stated.

The secretary of state’s office has operated under that interpretation ever since, Hurst says.

“Simply put, they’re wrong,” said Otter spokesman Jon Hanian, who also cited the 1978 ruling.

“The secretary of state and attorney general’s offices both confirmed there is no question that the veto is valid,” Hanian said.

Nate and Zollinger plan to file their legal challenge to the Idaho Supreme Court soon and hope the justices will reconsider the previous decision.

The threat of lawsuit is the latest example of growing dissent inside the Republican-dominated Statehouse.

Otter has issued down an unprecedented number of vetoes this year, prompting many Republican lawmakers to say they look forward to having a new governor in 2019 when Otter’s term ends. Otter says he is not running for re-election.

Some lawmakers have also said they want more power to overturn vetoes.

Under current law, state legislators cannot overturn vetoes after the legislative session has adjourned.

One proposal would allow them to do so after they adjourn.

It cleared the Senate in 2014 and 2016, but has been blocked both times in the House.