Democrats on the Legislature’s budget committee signed off early Thursday on an addition to the two-year budget headlined by the inclusion of a “millionaire’s tax” and Gov. Janet Mills’ proposed $300 “affordability checks” — and Mills appears likely to back both proposals if the Legislature agrees to keep them in the budget that reaches her desk.

The party-line nod of approval on the state’s supplemental budget came just before 12:45 a.m. Thursday from the Appropriations and Financial Affairs Committee. The inclusion of the extra tax on Maine millionaires appeared to set up something of a political showdown with the Democratic governor.

But about half an hour after the committee passed the budget, Mills weighed in with a statement approving of the hike.

“Throughout my time in office, we have made historic investments in health care, education, and local communities, all to help Maine people. It is crucial that we maintain these important investments for Maine people into the future,” Mills said in the statement. “So, when the Senate President and the House Speaker asked me whether I would support a surcharge on the very wealthiest in the supplemental budget in order to continue funding these investments, I agreed.”

Thursday’s move continues the pattern in recent years of Democrats using their majorities to pass budgets along party lines. Disagreements between Democratic and Republican appropriators revolved around moving several hundred million dollars from the state’s maxed-out “rainy day” fund to the General Fund to pay for proposals covering areas such as affordable housing, school bus safety upgrades and health care.

Democrats, to the ire of Republicans, made a number of those moves after 11 p.m. Wednesday.

The budget is now set to be voted on in each chamber. Once the House and Senate pass it, it will reach Mills’ desk. The Legislature is set to adjourn April 15.

Legislative leaders and the state’s fiscal policy office did not confirm the supplemental budget total Thursday, nor did they confirm how much money was pulled from the rainy day fund. But the governor’s budget proposal from earlier this year totaled about $275 million, which would raise the two-year state budget to about $11.9 billion.

Mills’ initial proposal looked to take about $300 million from the rainy day fund, including about $218.5 million that Mills had proposed setting aside to cover the $300 checks.

Mills wanted the checks to go to about 725,000 Mainers who meet income eligibility rules. However, lawmakers tweaked that plan, and if approved, the checks would now go to some 500,000 Mainers.

Mills, who is running for the U.S. Senate during her final year in the Blaine House, had previously vetoed a proposal that included a tax hike on wealthy Mainers. Her Democratic rival in the Senate primary, Graham Platner, had voiced support for a millionaire’s tax.

Democratic appropriators added the millionaire’s tax late Tuesday. It adds an income tax surcharge of 2% on the portion of a resident’s taxable income beyond $1 million for single filers, $1.5 million for heads of households and $1.5 million for joint filers.

The budget amendment put the millionaire’s tax revenue in the General Fund, and Mills noted in her statement that she wants the money set aside for specific purposes.

“I requested that that revenue be used in part to provide property tax relief for hardworking Maine people who are feeling the pinch,” Mills said in her statement. “The Appropriations Committee agreed, and I am grateful for their work on this initiative.”

The frustration and fatigue from Republican lawmakers on the committee grew as the set of late-night votes stretched on Wednesday. Rep. Ken Fredette, R-Newport, said he and his Republican colleagues feel the state has “a spending problem” rather than “a revenue problem.”

Rep. Drew Gattine, D-Westbrook, who chairs the budget panel and who introduced the millionaire’s tax amendment, argued that the policy is helping Mainers and funding key programs.

“I believe it’s a fundamental issue of tax fairness that we ask people with the very highest incomes in Maine to contribute a little bit more,” Gattine said Tuesday.

Rare moments of agreement between Democrats and Republicans included a small sales tax refund for timber harvesting equipment. Rep. Jack Ducharme, R-Madison, expressed thanks to Mills for including that in the budget.

But many more votes were along party lines, covering everything from not conforming with parts of President Donald Trump’s One Big Beautiful Bill Act to moving $22 million to a MaineCare reserve fund. The committee also included Mills’ proposal for a statewide ban on cellphones in schools and a long-sought effort to boost minimum teacher salaries.

Though the long night featured plenty of partisan disagreements, it wrapped up on a warmer note. With the clock ticking closer to 1 a.m., Fredette thanked Sen. Peggy Rotundo, D-Lewiston, the committee’s co-chair who is serving her final term, for her work over the years.

Staff Writer Randy Billings contributed to this story.