If there was a question of whether Nassau County taxpayers understood the impact of the newly passed Republican tax overhaul, it was answered last week when residents lined up to prepay their 2018 taxes.

Taxpayers braved chill temperatures and Town of Hempstead and North Hempstead employees worked long hours, including the Saturday and Sunday of a holiday weekend, to help residents avoid a $10,000 federal deduction cap on state and local payments in 2018.

Many county taxpayers understood very clearly that the cost of government had just gone up by thousands of dollars. And that the value of their homes could go down by as much as 15 percent.

This is a message that should be heard by every government in the state starting with school districts: the tax playing field has changed dramatically and not in a good way for Nassau County.

Sadly, even the efforts of taxpayers and town officials to prepay their taxes could all be for naught.

Gov. Andrew M. Cuomo of New York signed an executive order last week paving the way for residents to prepay their property taxes.

In an advisory notice posted to its website last Wednesday, the I.R.S. said that maneuver could work, but only under limited circumstances. To qualify for the deduction, property taxes not only need to be paid in 2017, they must also be assessed in 2017.

The I.R.S. also cautioned that the guidance it posted is advice to taxpayers and tax preparers, not a legal ruling. And the agency did not define what it means for a tax to be “assessed.”

Such is life when one party decides to please wealthy donors and ram through a tax plan without hearings, input from experts or contributions from the other party. With blue states in their cross hairs.

The tax plan could not happen at a worse time in New York.

The state faces a $4.4 billion to $6.3 billion deficit and the threat of losing billions more in federal aid. The losses could grow even more based on plans of the Trump administration and Republican-controlled Congress to cut entitlement programs such as Medicaid and Medicare.

The hope that the state could help offset the pressure on local government is dimmed by the state Senate Republicans, who have said their priority will be cutting taxes and fees.

If GOP state legislators prevail, Nassau County taxpayers should not expect an increase in state aid to local school districts. In fact, they will be lucky to not see decreases.

So what can be done?

Governors and legislative leaders in New York, California and other states are considering legal challenges to elements of the law that they say unfairly single out parts of the country, according to an article in The New York Times.

This includes possible changes to the state tax code to allow residents to take advantage of other federal tax breaks — in effect, restoring deductions that the tax law scaled back.

Companies have long sought to exploit loopholes in the tax code, The Times article points out. But until now governments have not.

We look forward to hearing what Gov. Cuomo has planned.

Whatever Cuomo comes up with it is clear New York must also begin looking at additional sources of revenue. State officials can begin by legalizing — and taxing — marijuana, as this page recently recommended, and go from there.

On the local level, more has to be done to reduce costs and encourage economic development.

The 56 school districts and dozens of villages and special districts are an obvious place to look to cut costs.

Nassau County residents take justifiable pride in the quality of their schools, and many people based their decision on where to live on the school district.

But with the cost of maintaining government services rising the questions needs to be what ways can more  — or at least the same — be done with less?

The county Legislature recently took a good step forward with the approval of an independent inspector general to investigate fraud and waste in county contracts. We would like to see that role expanded to all levels of government in the county.

As for development, the third track between Floral Park and Hicksville and the development plan proposed by the New York Islanders is a good start in a county has appeared if not hostile than at least indifferent to economic growth in the past.

Development of the Hub should be next. We look forward to what Nassau County Executive Laura Curran and the new county Legislature come up with to develop the Hub’s economic potential.

That should be followed with a plan to aid local shopping districts.

This much is certain: Nassau County is going to change — one way or another.