A Ramsey County judge on Wednesday struck down Gov. Mark Dayton’s veto of the state Legislature’s budget, saying the governor was wrong to use his constitutional authority to try to get lawmakers to renegotiate tax cuts and other policy issues.

In his ruling, Judge John Guthmann wrote that Dayton’s line-item veto in May of House and Senate funding amounted to “effectively eliminating a coequal branch of government” and that it violated the state Constitution.

“The governor’s line-item veto of the Legislature’s appropriations offended the Separations of Powers clause of the Minnesota Constitution,” Guthmann wrote in his 22-page ruling, adding that his decision rendered Dayton’s veto “null and void.” He added that Dayton’s veto “effectively abolished the Legislature.”

Dayton said soon after the ruling that he would appeal it. Republican legislative leaders, who filed the lawsuit that prompted the ruling, applauded the judge’s decision and urged the DFL governor to accept it as the final word on the matter.

But the governor said later Wednesday that the Minnesota Supreme Court should have the final say. “Today’s District Court ruling is only a preliminary step in this case’s judicial process,” Dayton said in a statement released by his office.

Still, Guthmann’s ruling deals a blow to Dayton’s attempt to force Republican lawmakers to renegotiate certain aspects of the state budget finalized in May, particularly some tax cuts that Dayton says are excessive and could harm the state’s finances in the coming years.

“I have worked hard to restore sound fiscal integrity to our State Government,” Dayton said. “My line-item veto was targeted to achieve this result.”

GOP leaders, meanwhile, said Dayton should not leave Minnesotans footing the bill for his pursuit of the lawsuit.

“The governor should accept this verdict and allow the people of Minnesota to move on instead of continuing to waste taxpayer dollars on expensive litigation,” said Senate Majority Leader Paul Gazelka, R-Nisswa.

House Speaker Kurt Daudt, R-Crown, said Dayton didn’t have a strong case for striking the House and Senate budgets, which threatened to force furloughs for hundreds of state lawmakers and legislative staff, disabling the Legislature’s operations.

“I think the governor did not have a strong case from the very beginning,” Daudt said.

In his ruling, Guthmann wrote that the state Constitution does grant wide-ranging veto powers to the governor. But he suggested that Dayton should have taken a different approach to address the concerns that prompted his veto of legislative funding. Dayton could have vetoed each of the bills that contained the policies he found problematic, Guthmann wrote; along with the tax bill, which included property tax cuts for business owners and a break in the state cigarette tax, Dayton also expressed concern about changes to teacher licensing requirements and a stricter prohibition on driver’s licenses for people living in the country illegally.

Dayton has previously explained that he didn’t want to veto the massive spending bills that included those provisions, fearing it would have led to a wide-ranging state government shutdown.

But by turning his veto pen toward the Legislature, Guthmann wrote, Dayton struck spending in an area where he never expressed any concerns: the budgets of the House and Senate.

“The court’s ruling is by no means intended to prevent governors from issuing a line-item veto of the Legislature’s appropriation if they actually object to the manner in which the Legislature funded itself,” the judge wrote. “No such concern exists in this case because the Governor concedes his vetoes had nothing to do with the Legislature’s appropriation.”

Dayton’s attorney, former Supreme Court Justice Sam Hanson, argued that the governor’s veto did not imperil the functioning of the Legislature because a court could order temporary funding — as happened in 2005 and 2011 when budget stalemates forced the state government into a partial shutdown.

But Guthmann rejected that argument, writing that “emergency funding is not a remedy for the unconstitutional acts by one branch of government against another — it is a remedy for citizens.”

Also Wednesday, Guthmann dismissed a separate lawsuit filed by a conservative watchdog group over lawmakers’ pay. The Association for Government Accountability sued the Legislature in June, trying to force it to implement a pay raise for lawmakers. Guthmann ruled that the group did not have standing to mount such a complaint.

Last year, Minnesotans voted overwhelmingly to strip lawmakers’ power to set their own salaries and turn the decision over to a citizen panel. That group voted this spring to approve lawmakers’ first raise in nearly two decades, from $31,140 annually to $45,000.

While Senate leaders followed the panel’s recommendation, the House did not, resulting in each chamber receiving different salaries. Daudt said Wednesday that the House would not raise salaries and that a court should settle the matter.

In his ruling against Dayton, Guthmann hinted that he did not appreciate that the courts would be pulled into a dispute between the other two branches of government.

“Unfortunately, the court must step in political quicksand whichever way it rules,” he wrote.