It appears that Gov. Butch Otter signed the veto past the mandatory deadline, making the veto irrelevant. Via Post Register:
There’s a court fight brewing over Gov. C.L. “Butch” Otter’s veto of a bill eliminating the sales tax on groceries.
Otter vetoed the bill, which had won veto-proof majorities in both the House and Senate, on Tuesday. Since the Legislature had adjourned for the year, there was no possibility for the House and Senate to attempt veto overrides.
But Wednesday in the law office of Idaho Falls attorney and ultraconservative Republican activist Bryan Smith, Rep. Ron Nate, R-Rexburg, and Rep. Bryan Zollinger, R-Idaho Falls, held a news conference to announce that they believe the veto came too late, after a constitutional 10-day deadline had passed. Grocery tax repeal, they argued, is now the law of the land, and will go into effect in 2018.
“Unfortunately for the governor, but fortunately for Idaho citizens, the veto came too late,” Nate said.
During the session, the governor has five days to veto a bill and return it to the Legislature following passage of a bill. But if the Legislature adjourns before that window runs out, as was the case with the bill repealing the grocery tax, the governor has 10 days to veto the bill.
The disagreement is over when the clock starts ticking.