US presidential debate: Barack Obama attacks Mitt Romney's integrity "I hear Governor Romney say he's a big coal guy - and keep in mind when - Governor, when you were governor of Massachusetts, you stood in front of a coal plant and pointed at it and said, "this plant kills," and took great pride in shutting it down. "And now suddenly you're a big champion of coal?," concluded Mr Obama, his voice heavy with scorn as he made the familiar charge that Mr Romney is a flip-flopper whose policy positions are driven by electability, not integrity. At other times the attacks from Mr Obama were downright cheap - as when he accused Mr Romney of bashing China while investing in Chinese companies that made surveillance equipment used by the regime in Beijing for internal spying. "Governor, you're the last person who's going to get tough on China," finished Mr Obama in a taunt that Mr Romney could not let pass. "Have you looked at your pension?," said Mr Romney advancing on the president, "Have you looked at your pension, Mr President?" he repeated, growing increasingly agitated, his voice shrill with indignation. I don't look at my pension. It's not as big as yours," flashed back Mr Obama, the smart kid in the playground, raising a ripple of laughter while neatly reminding the audience of his opponent's status as a rich man. Mr Romney did not absolutely fail this test - on the economy he remained equitable and plausible - but there were times when he clearly allowed Mr Obama's incessant poking and prodding to get under his skin, repeatedly quibbling with the moderator as he tried to respond. You'll get your chance in a moment. I'm still speaking," snapped back Mr Romney at one point when Mr Obama tried to interrupt a disquisition on his energy policies. Perhaps these are small things, but television debates are often decided not on policy, but on the broader sweep of a candidate's demeanour: presidents and would-be commanders-in-chief need, above all, to exhibit coolness under fire and last night Mitt Romney didn't always do that.