The most controversial new work of art in the United States is a sculpture that resides in an undisclosed warehouse location in Red Hook, Brooklyn. Hardly anyone knows where it is, and few have actually seen it. The people who commissioned the piece have warned the artist not to publicly identify himself. They don’t think they’re being paranoid. “We’ve gotten all kinds of hate mail,” Lucien Greaves, one of the people who commissioned the work, says. Greaves has received a number of emailed death threats, which he occasionally posts verbatim to his Facebook page: “I hope, I pray you get a bullet. You are evil your a monster, an obamanation…the evil radiates off you. I hope you suffer.” A guest on Don Imus’s show on Fox News remarked jocularly that Greaves and his cohorts behind the sculpture should be lined up next to it and shot. Greaves hadn’t seen the artwork in person until recently. On a warm afternoon in early June, a friend drove him down to New York from his home near Boston so he could take a look. He arrived in Brooklyn just as the sun was setting and hurried into the space where the sculpture is…