On the evening of August 19 local time, former US President Barack Obama appeared at the National Congress. In his speech, he stood up for Biden, his former vice president and presidential candidate, and did not mention Trump’s “crimes” one by one. After Obama and trump have been criticized, trump is not idle. He confronted each other at the news conference that night, saying “I’m here because of Obama and Biden (not doing well),” and tweeted several tweets to Obama. In the third night of the National Congress of the United States, the Museum of American Revolution in Philadelphia ushered in a heavyweight guest, former President Barack Obama. His appearance is just the endorsement of Biden, who was officially nominated as the presidential candidate the day before. < / P > < p > “I ask you to believe in your ability to fulfill your responsibilities as citizens and to uphold the basic principles of our democratic system.”. Standing in front of the text of the U.S. Constitution and facing the camera, Obama warned Americans that American democracy was “at stake” and urged voters to support his former Vice President Biden in the November general election. From the perspective of Trump’s personality, the attitude and manner of his opponents, his attacks on the media, and his poor anti epidemic performance In his speech, Obama listed the trump administration’s “crimes” one by one, and finally pointed out that he was not suitable to be president. “Trump is not up to the job because he can’t, and the consequences of failure are serious,” he said. 170000 Americans die, millions of jobs disappear Our worst impulses have been unleashed and our reputation around the world has been severely damaged. ” < / P > < p > “this administration has shown that if they are re elected, they will destroy our democracy. So we’re going to make an effort in the next 76 days and make a choice with the vote – for Biden and Harris. Only in this way can we be worthy of our hearts. ” In contrast, in this speech, Obama strongly supported Biden and Harris, calling Biden “brother.”. “Joe and I come from different places and ages, but I admire his toughness He will treat everyone he meets with respect and dignity. ” < p > < p > at the White House press conference held earlier on Wednesday, reporters read the draft of Obama’s previously disclosed speech, including Obama’s attack on trump. This undoubtedly angered trump. Trump retorted: “Obama didn’t do a good job in his term, and it’s because of Obama and Biden that I’m here now. If they did well, I would not be here. ” Just the day before, he hit back at Michelle Obama with the same words. < / P > < p > “welcome, Barack and the dishonest Hillary. See you on the battlefield During Obama’s speech, trump repeatedly tweeted Hillary Clinton, Obama and Biden’s deputy, Harris, to prove that he was following the live broadcast. In one of his tweets, trump questioned Obama’s motivation to support Biden now. “Why didn’t Obama support dawdling Joe until it was all over, even though it was too late?” he wrote? Why did he try to keep him out of the race? ” It is worth noting that trump also reprinted two tweets from US Republican Senator Lindsey Graham. Greenham is a close friend and staunch political ally of trump and currently chairs the Senate Judiciary Committee. Graham launched a fierce attack on Hillary Clinton and Obama, accusing them of “losing” by coming out to support Biden. In response, he also cited the “black history” of Obama’s presidency, such as deplorable foreign policy and weak economic growth. < p > < p > < p > the Capitol Hill newspaper pointed out that Obama’s sharp remarks were his most direct attack on trump in public so far. As a former president, Obama has occasionally expressed dissatisfaction with trump, but he has been out of the public eye except for the mid-term elections in 2018. In addition, CNN, Capitol Hill and other US media all believe that Obama’s endorsement of this appearance may provide impetus for Biden’s campaign, which is something few of them can do. A joint poll by politico and an advisory body found that 58% of registered voters have a good opinion of Obama. < / P > < p > after Obama’s appearance, the topic “President Obama” instantly jumped to the top of the US trend list on twitter. So far, there are 10000 tweets on this line. In addition, the topic of “omnipotent Obama” ranks seventh on the trend list, and is still rising.