"The idea is to evoke certain thoughts in the mind-set of the person who is looking at the ads," says a New York Muslim cleric who is backing a project to place ads promoting Islam in 1,000 MTA subway cars. They’re sure to provoke “certain thoughts” aplenty, especially with the NYC placements slated for September, during both the Islamic holy celebration of Ramadan and the anniversary of the 9/11 attacks. The ads feature phrases like “Prophet Muhammad?” and “Head Scarf?” on one side and the words “You deserve to know” and the Web address WhyIslam.org on the other. Rep. Peter King strongly opposes the campaign based on “those behind it,” including a Brooklyn imam who appeared as a character witness for convicted 1993 World Trade bombing mastermind Sheikh Omar Abdel-Rahman. The controversy’s intense. That’s a good thing, because in a free society, legitimate ideas merit debate, even in commercial messages. But the timing and venue here seem imprudent and provocative, with cramped and steamy late-summer subway cars providing prime breeding grounds for angry and profane ad defilers and those who would stir up hatred in worse ways. Buyer beware: you get what you pay for.