Gov. Chris Sununu is telling state officials to prepare for a possible budget veto, which would leave the state with no budget as of June 30.

A veto also would set the stage for weeks, if not months, of operating under funding levels authorized in the current budget.

In a letter to agency heads delivered on Friday, a copy of which was obtained by the Union Leader, Sununu calls the budget that passed the Democratically controlled House on Thursday one that “replicates the mistakes of the past.”

“A budget that does not protect New Hampshire’s best interests will be vetoed,” he writes.

“In the event that I must take action to stop an irresponsible budget, I ask that you and your staff begin to make the necessary preparations for the possibility of a continuing resolution on the state budget at current funding levels.”

If Sununu vetoes the budget, state agencies won’t run out of money and suspend operations, but most likely will be funded at current levels, assuming the legislature passes and Sununu signs a continuing resolution.

Anticipated new spending on mental health services, child protection and a host of other initiatives would be put on hold, but the DMV would continue to operate, roads would be maintained, state offices would remain open.

Sununu’s directive could be considered prudent, given the House has passed a budget at odds with the governor’s proposal in several key areas. But it is also no doubt intended as a shot across the bow of the Democratically controlled Senate as it begins its budget-writing process.

The governor gets to present his budget first, which Sununu did in February. The House takes that document and creates its own budget, but the House budget looks nothing like Sununu’s plan.

The only way a veto can be avoided is for the Senate to find some middle ground between the governor and House proposals. Sununu’s letter virtually assures that if the budget landing on his desk in June looks anything like the House-passed budget, a veto is coming.

“Our initial conversations with members of the Senate have been positive,” Sununu writes, “and it is my hope that the Senate will pass a budget that continues our state on a path of economic success.”

House Finance Committee Chairman Mary Jane Wallner, D-Concord, anticipates some compromise as well. She described the House budget as the Democrats’ opening offer.

“We’re on the first step of a long journey,” she said at the budget briefing for House members last week. “It’s a long way between now and June 30, and a lot of different things will happen. So probably what you’ll see in the final version of the budget will look a lot different than what you’re seeing today.”

Many agency heads got more money for their departments in the House budget than they got in Sununu’s budget, and his letter warns them to stick with the Executive Branch numbers as they begin their Senate testimony.

“Please remember as you and your staff prepare for your Senate budget presentations that you should advocate for appropriation levels consistent with our proposed FY 2020-2021 budget,” he writes.

“If there are programs that go beyond our proposed budget that you feel are worthwhile, you should propose realistic, programmatic reallocations from other areas of your agency.”

The last time a governor vetoed a budget was in 2015, when Democratic Gov. Maggie Hassan vetoed the budget passed by a Republican-led Legislature. Hassan signed a continuing resolution to fund state government for the next six months to avoid a shutdown.

The two sides negotiated through the summer and struck a deal in September that saw Hassan get the pay raises for state employees that she wanted, while Republicans got the cuts in business taxes they wanted.

The two sides this time around are far apart on business taxes, use of surplus funds from 2019, paid family and medical leave, education funding, DCYF positions, a secure psychiatric hospital and a host of other issues.

The Senate’s reputation as a place where compromise is more likely and partisanship not as intense will be put to the test in the upcoming weeks, as senators try to craft a budget the governor will sign.