By now the whole city knows about Mayor Giuliani’s getting engaged to Judith Nathan, right down to the details of the carats in Judi’s ring. We wish Mr. Giuliani all the domestic bliss in the world. But while he’s been off tending to his romance in Europe, promoting his book on a nationwide author tour, and fixing the Mexico City police, the city he loves has been veering off in the wrong direction. That detour has been led by a mayor, Michael Bloomberg, who a lot of New Yorkers voted for based on Mr. Giuliani’s endorsement. “I love this city, and I’m confident it will be in good hands with Mike Bloomberg,” Mr. Giuliani said in television commercials before the election. After the election, John Podhoretz wrote in the New York Post, “The good news is that Michael Bloomberg owes his mayoralty to Rudy Giuliani. Never before in the annals of political endorsements has one politician done so much for another — 27 percent of those who voted said Rudy’s full-throated effort for Bloomberg had affected their choice in a positive way.”

It’s not that Mr. Bloomberg hasn’t been without his own successes. Winning mayoral control of the public schools and disbanding the unaccountable Board of Education was a huge victory, and, until last week, Mr. Bloomberg had managed to stand firm against tax increases. But now that Mr. Bloomberg is facing a $6 billion gap in the city’s $42 billion budget, he seems to have undergone a transformation into an invertebrate. Mr. Bloomberg is raising taxes with alacrity in what is already a high-tax city. At the same time, Mr. Bloomberg is insisting — “risibly,” as Steven Malanga put it in the Wall Street Journal — that there’s hardly any room for cutting city expenditures.

Mr. Giuliani and his spokeswoman, meanwhile, have maintained a steadfast silence on Mr. Bloomberg’s default. There’s a longstanding and probably wise guideline that says politicians who have recently left office should let a decently polite interval pass before criticizing their successors. By our lights, that interval, in this particular case, has passed. The tax-and-spend caucus of Mr. Bloomberg and the City Council has gone so far as to suggest that the city’s current budget problems are the fault of Mr. Giuliani. One is left to guess what Mr. Giuliani thinks by reading what his former aides like J.P. Avlon and Tony Coles are writing in the newspapers. Here’s hoping Mr. Giuliani interrupts his wedding planning for a break long enough to make his views on the budget known with his characteristic directness — and to save his own legacy and his city from the damage being inflicted by the mayor that Mr. Giuliani endorsed.