The 2016 presidential campaign has broken the mold in so many ways. Start with the first woman major-party nominee in Hillary Clinton and practically everything about Donald Trump’s candidacy. Now, add President Obama’s role as an attack dog.

　　2016年的美国总统大选在很多方面都打破了常规。先是主要政党总统候选人的提名人第一次是位女士--希拉里克林顿，然后是有关唐纳德·特朗普的竞选资格问题。现在又加上奥巴马总统像警犬一样的攻击角色。

　　At the Democratic National Convention last week, Mr. Obama launched a withering attack on the Republican nominee, accusing Trump of selling the American people short, cozying up to autocrats, and offering no solutions.In his choicest dig – a warning about “homegrown demagogues” – Obama alluded to the billionaire-turned-politician, but didn’t mention Trump by name.

　　在上周举行的民主党全国代表大会上，奥巴马先生对共和党候选人发起了猛烈攻击，指责特朗普卖空美国人民，取悦独裁者，并且没有提出任何解决办法。在他精心选择的讽刺中——一个关于“本土煽动者”的警告 ——奥巴马暗指百万富翁变成了政治家，但是奥巴马没有提到特朗普的名字。

　　This week, Obama became even more pointed. “I think the Republican nominee is unfit to serve as president,” he said flat out on Tuesday. Two days later, Obama warned the candidates that “if they want to be president, they got to start acting like president.” He used the plural “they,” but everyone knew who he was talking about.

　　本周，奥巴马变得更加直截了当。 “我认为共和党候选人不适合做总统，”他在周二直率地说。两天后，奥巴马警告总统候选人说“如果他们想做总统，他们得开始像总统一样做事。”他在这里用了复数“他们”，但是大家都知道他在说谁。

　　To some, Obama’s comments have been a welcome addition to the chorus, and an appropriate use of the presidential megaphone to warn against a potentially dire outcome in November: the election of someone who could pose a threat to American democracy. To others, Obama’s statements are inappropriate and demean the presidency.

　　对一些人来说,奥巴马的言论很受欢迎，不仅仅是因为众口一致，而且是用一种合适的方式来使用总统扩音器警告11月份可能出现的潜在的可怕结果：选举某个人可能威胁到美国的民主。而对于其他人来说,奥巴马的讲话是不合适的，并且贬低了总统这个职位。

　　Either way, scholars say, Obama’s thorough trashing of the opposing party’s presidential nominee is unique for the modern era, compared with how other recent presidents have handled the race for their succession.

　　无论哪种方式，学者们说，同近期的总统们在如何处理他们继任者的竞争上相比较，奥巴马全面诋毁反对党总统候选人是现代时期独一无二的。

　　“It is unprecedented certainly in post-World War II American history,” says Cal Jillson, a political scientist at Southern Methodist University in Dallas.

　　“这是二战后美国历史上前所未有的,”来自达拉斯南卫理公会大学的政治学家Cal Jillson说道。

　　Obama, too, has a personal reason to go after Trump: the billionaire’s persistent allegations that the president wasn’t born in the United States. But Obama’s critique of Trump doesn’t seem to stem largely from personal pique; it reflects Trump’s performance as a candidate over the past year, and widespread public doubts about Trump’s temperament and qualifications to be president.

　　奥巴马抨击特朗普也有其个人原因：这个亿万富翁持久指控奥巴马总统不是在美国出生。但奥巴马对于特朗普的批判看起来似乎不是基于个人的愤怒;他的批判反映了特朗普在过去一年里作为总统候选人的表现，反映了公众普遍对于特朗普担任总统的气质和资格的怀疑。

　　Still, aside from Truman, historians don’t see many past retiring presidents working hard either to elect the nominee of their own party or defeat the other party’s candidate.

　　除了杜鲁门之外,历史学家没有发现许多过去退休的总统们在努力工作以便选出自己所在政党的被提名人或者击败另一政党的的候选人。

　　For Obama, not only are the full-throated attacks on Trump unprecedented for the modern era, so is the full embrace of Mrs. Clinton. In his convention address, Obama declared that “there has never been a man or a woman, not me, not Bill, nobody more qualified than Hillary Clinton to serve as president of the United States of America.”

　　对于奥巴马来说,不仅对于特朗普进行高调的攻击在现代这个时代是空前的，而且克林顿夫人对于他的支持完全接受也是空前的。在他的大会讲话中,奥巴马宣称,“从来没有一个男人或一个女人,不是我,不是比尔,没有人比希拉里更适合作为美利坚合众国总统。”

　　Obama’s enthusiastic support for Clinton is the exception in modern presidential history. “Oddly enough, circumstances have often for one reason or another prevented a sitting president from actively campaigning for a successor,” says historian David Pietrusza.

　　奥巴马对于克林顿的热情支持是现代总统历史上的一个例外。“奇怪的是,情况往往因为这样或那样的原因阻止了现任总统积极争取继任者,”历史学家David·Pietrusza说。

（编辑：何莹莹）