Now, however, as it prepares to mourn its fallen heroes yet again, the department faces another challenge. Soon, thousands of would-be firefighters will take a civil service test in hopes of qualifying for a job with the FDNY. It will be the first such test given in four years, and it will be one of the most important such tests given since FDNY reformers insisted on qualifying tests more than a century ago.

Simply put, the FDNY is too white and too male. At a time when the Police Department has become a model of diversity, at a time when other fire departments around the country have found a way to incorporate and even welcome women as colleagues, the FDNY’s overwhelmingly white male work force is an anachronism. Worse, it is a court case waiting to be made.

Fire Commissioner Salvatore Cassano knows what is at stake when new hiring begins. If the department’s hiring practices continue as usual, lawsuits on behalf of women and minorities inevitably will be brought, and a judge could order a new round of testing. That would delay the hiring of young new recruits and inevitably add to tensions in the city’s firehouses.

So Commissioner Cassano is spending the summer in minority neighborhoods, encouraging underrepresented groups to prepare for and take the test. But encouragement isn’t enough—the commissioner has to reassure women and minorities that they are welcome in the firehouse. That has not always been the case, as more than a few women and black firefighters have said publicly.

New York has made great strides ameliorating racial tension in the city over the past decade. But the lack of diversity in one of the city’s most storied departments remains a sore point. This needs to be fixed, now, so that the new class of the Bravest looks more like New York City.

One upstate Republican state senator is showing the way. Undecided until just this week, Senator James Alesi, who represents a district near Rochester, announced on Monday that he will support the bill. Mr. Alesi’s announcement could be critical to passage: he is the first Republican state senator to support the bill. Passage in the Republican-controlled Senate will require several G.O.P. votes; otherwise, the measure will be pulled from the legislative calendar. Governor Cuomo, one of the bill’s most forceful supporters, has said he doesn’t want gay marriage to suffer defeat again in the Legislature.

For many of the uncommitted senators, the issue surely is emotionally charged. But in its essence, gay marriage is a matter of civil rights. That’s precisely the argument that persuaded Senator Alesi. “I believe that if you live in America and if you expect equality and freedom for yourself, that you have to extend it to other people,” he said.

The measure now has the support of 30 senators—29 Democrats and one Republican. Seven senators, including two from New York City (Republican Andrew Lanza of Staten Island and Democrat Joseph Addabbo Jr. of Queens), remain uncertain. Supporters need two more votes to ensure passage.

The time for uncertainty is over. It’s time for these politicians to act like leaders by embracing equality and civil rights for gay people.