One of the most interesting political questions in this city is what Mayor Bloomberg is going to do about the race in the 5th Councilmanic District. This is where Republicans have chosen Jennifer Arangio to run against the Democratic tax-raiser, Gifford Miller, who is speaker of the Council and the mayor’s main negotiating partner in the budget battles in the city. The drama arises from the fact that the mayor is a poorly disguised Democrat serving as a Republican, who has worked with Mr. Miller to pass anti-Republican policies. Some reckon Mr. Bloomberg will virtually have to endorse Ms. Arangio, if only to save face with the Republican Party. Not only will he need the Republican nomination down the line if he runs for re-election two years hence, but he is hosting the Grand Old Party’s national convention next year.

But it remains an open question how energetically Hizzoner will support Ms. Arangio. Back when she was still battling out this year’s only Republican primary in the city, our mayor actually declared of the Democratic speaker in an interview on New York One, “If [Mr. Miller] were in my district I’d probably vote for him. I think he’s doing a good job.”Ms. Arangio, who is nothing if not gracious, underplayed the gaffe at the time, telling the Sun,”I was quite surprised.” But if Hizzoner saw anything erroneous in his remarks, he didn’t deign let on to the public.

Recent trends, however, may be sobering him up. Reeling from the tax revolt that is taking hold in Brooklyn and Staten Island in the wake of his 18.5% property tax increase, Mr. Bloomberg has expressed interest in repealing his fiscal folly. Mr. Miller has indicated that he would be a barrier to any such move. Ms. Arangio, meantime, has given support for the Urban Republican Platform, which hews to core Republican principles like lowering taxes and removing barriers to building, while downplaying the social issues through which the national Republicans have alienated many in New York. The Sun endorses her candidacy warmly, and many will be watching to see whether Mr. Bloomberg will try to slip by with only grudging support for this upstart Republican so that he can maintain his pact with the city council’s Democratic camarilla.