The run-up to the resumption Tuesday of the 90th session of the Minnesota Legislature has been remarkably calm, given all that has happened since the last regular session adjourned in May 2017. The ill feeling between Gov. Mark Dayton and the Republican-controlled Legislature that contributed to a line-item veto of the Legislature’s operating budget and a monthslong legal battle seems to have subsided. Dayton won in court but has said he will sign a bill restoring the funding.

Our prediction: The lull won’t last. This is, after all, an election year.

Dayton is not running again, but several legislators are angling for his seat, and others are keen to give their party’s candidate an edge. The entire state House is on the ballot as usual.

And in the Senate, which is not up for election this year, the partisan alignment stands at 33-33-Fischbach. A district court judge last week opted not to rule on whether Lt. Gov. Michelle Fischbach can be state Sen. Michelle Fischbach, too. But the judicial branch is expected to get another shot at deciding her status — and potentially deciding whether the Senate has a functional majority. We’re rooting for the courts to settle the question soon and decisively.

But election-year positioning won’t be the whole story. Neither will the drama center on the customary even-year obligation to fund public-works projects with a major bonding bill — though meeting that obligation is by no means routine. Bonding bills failed to pass in 2004, 2007 and 2016; the three-fifths supermajority required to enact them demands more bipartisanship than the current political environment easily affords.

Rather, the session’s main event will be in the House and Senate taxes committees. The state implications of the changes in federal tax laws enacted by Congress in December are both sweeping and mind-­boggling. Deciding how to respond is sure to bring to the fore the deep disagreement that exists between Minnesota’s Republicans and DFLers over tax-policy fundamentals. What constitutes fairness, simplicity and revenue sufficiency? When those principles are in conflict, how should they be balanced? With state government divided, those are questions that will need bipartisan answers before the session’s end, set for May 21 by the state Constitution.

The Star Tribune Editorial Board will follow the tax issue and say more about it in weeks to come. For now, we urge legislators to avoid making tax policy promises until the full implications of the federal changes are better understood.

Dayton and GOP leaders say they want to spare Minnesotans from the large automatic state tax increase that the federal changes will bring beginning in 2019 if the state does not act. That’s a worthy goal. But sparing everyone — including businesses — could cost the state treasury more than it can responsibly afford, particularly in light of 2017 state property tax changes that will give businesses an ever-larger tax reduction in the coming decade.

Further, “conformity,” or linking the state’s tax code to the federal one in the same manner as it has been for 30 years, would offer taxpayers simplicity but also produce undesirable results. For example, Minnesota’s income tax would no longer include an adjustment for family size. And state tax breaks would flow to many higher-income people who already pay a lower share of their income in state-plus-local taxes than lower-income Minnesotans do.

The tax battle will be fought as other legislative committees deal with demands for state spending increases, even though 2018 is not a biennial budget-setting year. A high priority attaches to several of those calls. The Legislature must resolve the technical snafu that has bogged down the state vehicle license and registration system — and along the way, learn how to prevent future IT train wrecks in state services.

It must beef up investigation and enforcement of state laws protecting residents of senior living facilities from abuse — a duty that the state has failed to meet, as a Star Tribune series recently detailed. It must shore up the funding of public employee pension funds — and keep the pension bill free of the political poison pills that have been attached to it in recent years. It ought to approve a modest raise for state employees, which was held up by GOP legislators on a compensation committee in October for reasons that appeared related to the Legislature’s court fight with the governor, then in progress.

Plenty of other pleas for more spending will come. Mental health services, child care for low-income families and cities that benefit from local government aid are among those who deserve a hearing. But legislators will do well to respond with restraint, employing one-time money where possible rather than creating new ongoing obligations. The uncertainty on the tax side of the state’s budget ledger is good reason to avoid major new commitments on the spending side.

Not all of legislators’ time will be spent on money matters. The Legislature’s long-running gun policy argument got new impetus with last week’s school shooting in Parkland, Fla. We hope that tragic news tamps down enthusiasm for bills that legitimize gun violence — such as the “stand your ground” bill that awaits action on the House floor — and builds interest in measures to keep guns away from people with a history of violent behavior.

As he enters what will be his last legislative session as governor, Dayton has the future on his mind. “One of the most important legacies I want to leave is fiscal stability and honest budgeting,” he told the Editorial Board last week. “It’s important to me to protect Minnesota as much as possible” from the adverse consequences that he expects from the budget decisions that are being made in Washington.

That’s a fitting gubernatorial priority, and it ought to be a legislative priority as well.