TALLAHASSEE -- After a much-maligned parking garage contract with the Miami Marlins baseball team left the city of Miami on the hook for a huge property tax bill, South Florida state lawmakers came to the rescue with a proposal to save the city millions. But their attempt to tweak state law in Miami’s favor has run into a massive roadblock: the Florida Constitution.

A new sharply worded analysis by Florida House staff found that the proposal, filed by Rep. Jose Felix Diaz and backed by Rep. Carlos Lopez-Cantera, both Miami Republicans, likely runs afoul of the state’s Constitution.

The analysis, released Tuesday, states: “In the instant case, it appears that the Legislature is … statutorily providing an exemption for municipal property that is not used exclusively for municipal or public purposes, and that this exemption could be subject to constitutional challenge.”

Translation: Under the Constitution, Miami may have no choice but to pay a huge property tax bill, if Miami-Dade County decides to send the city a bill and push the constitutional argument.

The analysis came to the same conclusion that Miami-Dade Property Appraiser Pedro Garcia reached last year: The 5,700-space parking facility, which the city is leasing to the Marlins, does not constitute a “public purpose,” a requirement for a government entity to get a tax break.

In November, Garcia told the city that it may be liable for property taxes, estimating that the annual bill could be as high as $2 million. Expecting to qualify for a government tax exemption, city officials were surprised to learn of the possible bill. The Marlins washed their hands of the matter, pointing to a clause in their contract that left the city responsible for all taxes on the facility. The new $642-million stadium, which opens this spring, was financed mostly with taxpayer money and has been criticized as a windfall for the Marlins.

More taxpayer dollars could be going to the stadium project if Miami is not able to avoid paying the property taxes, estimated to be $1.2 million a year.

The tweak to the state law, which Diaz filed as a four-line amendment to a sweeping 33-page tax law, was aimed at helping Miami dodge the tax bill. Until now, Diaz’s amendment has escaped scrutiny, passing through its first committee stop unanimously and without debate.

Now, the amendment could face an uphill battle in the wake of the report highlighting its constitutional weakness.

The staff analysis points to a 2001 Florida Supreme Court case that found that regular, for-profit use of a government building by a private entity essentially disqualifies the building from receiving a property-tax break.

In that case, the Sebring Airport Authority in Highlands County leased some of its land to the Sebring International Raceway, a for-profit company that operated a raceway on the site. The airport authority, a government-entity, then tried to claim a property-tax exemption, claiming that the raceway served a public purpose

The Supreme Court’s response: “We disagree.”

The court found that “serving the public and a public purpose, although easily confused, are not necessarily analogous.” The ruling went on to say that leasing out the government property to a for-profit company does not serve a governmental purpose even if it is beneficial to the public.