President Barack Obama is asking voters to elect Democrat Hillary Clinton or risk dangerous policy changes by Republican Donald Trump.
美国总统奥巴马让选民选择民主党人希拉里·克林顿（Hillary Clinton）或是冒共和党人唐纳德·川普（Donald Trump）上台导致政策变化的风险。
But Clinton, who made history as the first woman to win a major party presidential nomination, faces a historical problem.
但是作为第一位赢得一家重要政党的总统候选人提名并创造了历史的女性，希拉里面临着一个历史难题。
Only once since 1960 has a two-term president been replaced by a candidate from the same party. Democrat Clinton is trying to succeed Democrat Obama, who ends his 2nd term as president on January 20, 2017.
自1960年以来，连任两届的总统被同一党派候选人接替的事情只发生过一次。而民主党人希拉里正试图接替2017年1月20日第二任总统期满的民主党人奥巴马。
Clinton is scheduled to accept the Democratic presidential nomination on Thursday at the party's convention in Philadelphia, Pennsylvania. Trump, a wealthy businessman, accepted the Republican nomination in Cleveland, Ohio, last week.
希拉里定于周四在宾夕法尼亚州费城的民主党大会上接受民主党总统候选人提名。富商川普上周在俄亥俄州克利夫兰市接受了共和党总统候选人提名。
Voters want change
选民希望变革
It is difficult to succeed a two-term president of the same party because voters often want change, said Matthew Kerbel. He is the chair of the political science department at Villanova University in Pennsylvania.
马修·坎贝尔(Matthew Kerbel)表示，同一党派很难继任一位连任两届的总统，这是因为选民通常希望变革。坎贝尔是宾夕法尼亚州维拉诺瓦大学政治科学系主任。
"It will be tough for Hillary Clinton to make a credible argument that she will bring a change in direction," Kerbel said. "What Hillary has going for her is that Donald Trump hasn't yet sold the nation on the type of change he would bring if elected president."
坎贝尔称，“希拉里很难让人相信她将会带来一种方向上的变革。对希拉里有利的是，川普尚未让全国人民对他如果当选后可能带来的这种变革感兴趣。”
The one time in the last 56 years a candidate succeeded a two-term president of the same party was in 1988. Republican George H.W. Bush beat Democrat Michael Dukakis to succeed Republican President Ronald Reagan. Bush was Reagan's vice president and some called his election, "Reagan's third term."
过去56年发生过一次候选人继任同一党派连任两届的总统，那是在1988年。当时共和党人老布什（George H.W. Bush）击败民主党人迈克尔·杜卡基斯（Michael Dukakis）接替了共和党人总统罗纳德·里根（Ronald Reagan）。老布什曾是里根的副总统，有人称他的当选是里根的第三任期。
All other efforts since 1960 failed.
自1960年以来其它努力都失败了。
In 1960, Republican Richard Nixon lost to Democrat John F. Kennedy, as he tried to succeed two-term Republican President Dwight Eisenhower.
1960年，共和党人理查德·尼克松（Richard Nixon）试图接替连任两届的共和党人总统德怀特·艾森豪威尔（Dwight Eisenhower），但是败给了民主党人约翰·肯尼迪（John F. Kennedy）。
In 1968, Democrat Hubert Humphrey lost to Republican Nixon to succeed Democrat Lyndon Johnson. Johnson served the final 14 months of Kennedy's first term and then four more years after his election in 1964. Nixon won a 2nd term in 1972.
1968年，民主党人休伯特·汉弗莱（Hubert Humphrey）在接任民主党人林登·约翰逊（Lyndon Johnson）上败给了共和党人尼克松。约翰逊接替了肯尼迪第一个总统任期内的最后14个月，然后1964年当选再次获得四年任期。尼克松在1972年赢得了第二个总统任期。
Republican Gerald Ford, who became president after Nixon resigned in 1974, lost the 1976 presidential election to Democrat Jimmy Carter.
1974年，共和党杰拉尔德·福特（Gerald Ford）在尼克松辞职后成为总统，但是在1976年的总统选举中败给了民主党人吉米·卡特（Jimmy Carter）。
In 2000, Democrat Al Gore lost to Republican George W. Bush. Gore was trying to succeed Democrat Bill Clinton, Hillary's husband, who served two terms as president. Gore was Clinton's vice president.
2000年，民主党人阿尔·戈尔（Al Gore）败给了共和党人小乔治（George W. Bush）。戈尔当时正试图接替任满两届的比尔·克林顿（Bill Clinton），也就是希拉里的丈夫。戈尔是克林顿的副总统。
In 2008, Obama defeated Republican John McCain. McCain was hoping to replace George W. Bush. McCain asked Bush not to campaign for him. Bush was unpopular because of a major economic collapse in 2008 and an unpopular war in Iraq.
2008年，奥巴马击败了共和党总统候选人约翰·麦凯恩（John McCain）。麦凯恩原本希望接替小布什。麦凯恩让小布什不要为他助选。小布什不受欢迎是因为2008年一场重大经济危机和一场不得人心的伊拉克战争。
At the convention on Tuesday night, all speakers talked about Hillary Clinton's historical achievement but one – Bill Clinton. The former president had this to say about his wife: "She's the best darn change-maker I've ever met in my whole life."
在周二晚上的共和党大会上，所有发言人都谈到了希拉里的历史性成就，除了她丈夫比尔·克林顿。这位前总统这样形容他的妻子，“她是我一生中见过的最好的变革者。”
Obama to campaign for Clinton
奥巴马为希拉里助选
Clinton has said she wants Obama to campaign for her and Obama has said he will do so often between now and the Nov. 8th election. A Washington Post/ABC News poll last month said 56 percent of Americans view Obama favorably, his highest rating in five years.
希拉里表示她希望奥巴马为她助选，而奥巴马表示会在现在和11月8日大选之间经常这么做。华盛顿邮报和ABC新闻上个月联合进行的民意调查表示，56%的美国人对奥巴马评价很高，这是他5年以来最高的一次评价。
Obama beat Clinton for the 2008 Democratic presidential nomination. But he said, "there has never been a candidate better prepared for the presidency than Hillary Clinton."
奥巴马击败克林顿赢得2008年民主党总统候选人提名。但是他表示，“没有任何参选人比希拉里更有资格出任总统。”
The president also criticized Trump for failing to "spend a lot of time trying to find out about issues," such as U.S. nuclear defense options, or the difference between Sunni and Shia Muslims.
奥巴马还批评川普未能花很多时间去厘清一些问题，例如美国核防御方案，或是逊尼派和什叶派穆斯林之间的区别。
Trump responded Wednesday by saying it is Obama and Clinton who are not prepared to lead the country.
川普周三回应称，正是奥巴马和克林顿没有准备好领导这个国家。
On Wednesday, he called Obama "the most ignorant president in our history" and "a disaster."
川普周三称奥巴马“是我国历史上最无知的总统，”是一场“灾难”。
"And I believe Hillary Clinton is even worse," he said.
他还表示，“我认为希拉里（比奥巴马）更糟。”(51VOA.COM对本文翻译保留全部权利，未经授权请勿转载，违者必究！)