If the proposal is approved in a public referendum on Monday, the borrowing could trigger up to a 4 percent property-tax hike, according to the Nassau Interim Finance Authority. That would force the Nassau County Legislature either to vote to override the cap -- which limits increases in property tax levy collections to 2 percent or the rate of inflation, whichever is less -- or reduce the tax levy by enough to avoid triggering the cap, officials said.
If the legislature chooses to vote to override, the tax-cap law mandates that such a vote would require at least a 60 percent "supermajority" of voters or the local governing body -- in Nassau's case, 12 of the 19 county legislators.
But it would not require the legislature to take annual votes because the borrowing should result in a one-time-only tax hike, officials said.
"It's a one-time vote on that increase because once it's done, it creates a new [tax] base," said Nassau County Attorney John Ciampoli.
The referendum asks voters for permission to borrow up to $400 million primarily to build a new Nassau Coliseum and a minor league baseball park.
NIFA, which took control of the county's finances in January, says the borrowing, including interest over 30 years, would lead to a 3.5 to 4 percent property-tax increase for the average county homeowner in 2012.
Nassau officials argue those costs would be offset by revenue that would come from the new Coliseum and baseball stadium.
Nassau could avoid exceeding the cap by finding up to 2 percent in corresponding property tax cuts elsewhere in its budget.
A vote to override the tax cap would be required well before any revenue from the new facilities begins flowing in, county officials said. The vote would occur by Oct. 31, the deadline for enacting the county's fiscal 2012 budget, said Katie Grilli-Robles, a spokeswoman for Nassau County Executive Edward Mangano.
With Robert Brodsky