For four days starting later this month, our city will become the focal point of the federal government, terrorists, and protesters. We cannot afford any manufactured challenges heaped on our real ones.

That’s why the unions’ belated decision to exploit the attention and go back on their word by threatening a strike is dishonorable and beneath them. It is a selfish September 10 attitude in a post-September 11 era. They should know that better than anyone.

It is true that New York City’s public safety heroes are not paid enough. But harassing the mayor and threatening the city’s safety during the Republican National Convention won’t help matters, just increase resentments and unnecessary divisions. Moreover, the timing of the threatened strike has a partisan edge, seeming like a union effort to encourage chaos when the Republicans come to town. Public safety should never become a partisan issue.

In 1919, when Calvin Coolidge was governor of Massachusetts, he faced a police strike that agitated for higher wages and shorter work in the wake of World War I. More than a thousand police officers, nearly three quarters of the total force, unilaterally enacted a work stoppage in an effort to establish collective bargaining. Coolidge called in the state militia, famously stating, “There is no right to strike against the public safety by anybody, anywhere, any time.” This is still a good guiding principle.

After working without a contract for the last two years, the police and fire unions have grown increasingly militant in an attempt to force the mayor’s hand on the eve of the convention. Protesters are following the mayor to public events and waiting outside his home. The tone of their tactics has grown more confrontational and less civil. Chants berating the mayor’s press secretary, Ed Skyler, for gaining a raise may have some abstract merit on policy grounds, but shouting “Eddie, we know where you live,” as the New York Times reported they did, crosses the line into cheap intimidation and personal attacks.

Nothing short of giving away the store in a gesture of generational fiscal irresponsibility would make the police unions happy. Even Mayor Giuliani, routinely attacked by the left as being a reflexive defender of the police, was accosted on parade routes for opposing unreasonable demands for police raises. This was not a gauge of Mr. Giuliani’s support of the police, but of his sense of larger responsibility for protecting the long-term fiscal stability of the city.

There is simply no way to give the uniformed forces the kind of double-digit raise they would like without sliding us into bankruptcy. Down the road, if the police and fire unions want to improve their wages, they should support the mayor in comprehensive efforts to dramatically reduce non-essential city headcount.

But all of this is academic and exploitative in the face of the challenges facing the city in the coming weeks. At the same time that the police and fire unions are backing off their commitment not to strike during the convention, protesters are calling for a mass abandonment of their agreement with the city in a march toward central park.

This will intentionally provoke a major conflict between protesters and the police, as the city defends the rule of law. Some of the self-styled anarchists who are coming to town want to cause disturbances to promote their cause even as they rely on the rule of law to stop their heads from getting kicked in. Fewer police and more protesters itching for trouble is a bad combination for a civil society. There are people who want our city to suffer during the next few weeks. Who thought that among their ranks might not only be Americans, but also members of New York’s Finest and Bravest?

At this point, it’s worth defending the obvious – the convention is good for our city and the nation’s politics. Remember that the Bloomberg administration lobbied to have both conventions come here in a sign of unity and solidarity after the attacks of September 11. The Democrats demanded that they be granted exclusive rights; were rebuffed and moved their convention to Boston. The Republicans made no conditions and came here of their own accord, bringing with them an always welcome boost to our economy.

The GOP also deserves some credit for coming here with very little hope of winning the state – a traditional consideration when picking a host city for your convention. It represents a leap of faith, at least an attempt to bridge the urban and rural divides between blue- and red state America. We should in turn attempt to meet their good faith at least halfway. Working together to ensure unity and public safety is a reasonable place to begin, remembering as we stare down the danger posed by terrorists that “There is no right to strike against the public safety by anybody, anywhere, any time.”