BOISE, Idaho — Proponents of lawsuit claiming Gov. C.L. “Butch” Otter took too long to veto a contentious grocery tax repeal bill argue the Idaho Supreme Court should look at the plain language in the state Constitution.

Idaho Falls attorney Bryan Smith, representing 30 state lawmakers challenging Otter’s veto, presented his argument in front of the state’s highest court Thursday. According to Smith, previous justices made the wrong decision nearly 40-years-ago when ruling how long a governor has to quash legislation.

“Don’t think there wasn’t a political risk for these 30 lawmakers to file this petition,” Smith said. “If we do not reward pioneers who defend the constitution, then unfortunately there will be a discouragement to bring cases such as this to this court.”

The lawsuit was filed in April after Otter vetoed legislation that would have repealed the state’s 6 percent sales tax on groceries. A handful of lawmakers have pushed for years to remove the tax on food and beverages, but faced resistance from legislative leaders. Lawmakers managed to work around leadership this year by completely rewriting a separate proposal during an amending session and securing enough supporters in both the House and Senate.

Otter had alerted lawmakers of his opposition before the bill was at his desk, arguing that the bill’s estimated $80 million cut to the general fund could negatively impact Idaho’s public school budget.

However, GOP lawmakers pushed the bill through anyway, making it a defining accomplishment during the 2017 session. Otter then received the grocery tax repeal bill on March 31, but issued his veto on April 11 — 11 days after adjournment.

In 1978, court justices issued a 3-2 ruling that a governor has 10 days to veto or approve a bill starting only after it lands on his desk. However, lawmakers upset with Otter’s veto decision have countered the Idaho Constitution plainly says the deadline kicks in after the Legislature adjourns.

Deputy Attorney General Brian Kane, representing the state, told the justices that Otter vetoed the bill and Secretary of State Lawerence Denney verified the governor’s decision because they were following the court’s prior decision. Kane warned that if the court overturns that decision, state leaders will be punished for following the law.

“State actors, like the governor and secretary of state, will be forced to ask ‘Did the court really mean what it said?'” Kane said.

The Idaho Constitution states that a governor has five days to veto or approve legislation when the Idaho Legislature is in session. It goes on to say that governor’s deadline is extended if the “legislature shall, by adjournment, prevent its return,” allowing a governor to veto a bill “within 10 days after such adjournment (Sundays excepted) or become law.”

This language prompted Justice Joel Horton to say “I’m having a great deal of trouble finding ambiguity within the phrase ’10 days after adjournment.'”

The court is expected to issue a ruling within the next few weeks.