What's Behind Trump's Criticism of ObamaU.S. President Donald Trump is facing a crowded field of 2020 Democratic presidential candidates. But when the president speaks, it is Barack Obama - his predecessor - who takes the brunt of Trump's barbs and insults. Trump has criticized the former president on issues ranging from U.S. policy in Syria to trade negotiations with China to the amount of time Obama spent playing golf during his presidency. Trump’s latest criticism came at the G-7 summit press conference in France this week when he claimed Russian President Vladimir Putin had “outsmarted” Obama by annexing Ukraine's Black Sea peninsula of Crimea. Trump mentioned Obama in 246 tweets An analysis of the president’s tweets in the Trump Twitter Archive shows that Obama was mentioned or berated 246 times during Trump's 951 days in office. That compares with Trump's 313 mentions of former Secretary of State Hillary Clinton, Trump's 2016 Democratic rival for president and favorite target for insults. Obama’s negotiation of the Iran nuclear deal -- which Trump disavowed after taking office -- often figures in Trump’s tweets. For example, the president wrote on June 21 that "President Obama made a desperate and terrible deal with Iran - Gave them 150 Billion Dollars plus I.8 Billion Dollars in CASH! Iran was in big trouble and he bailed them out. Gave them a free path to Nuclear Weapons, and SOON. Instead of saying thank you, Iran yelled...” Experts say criticism of a former commander-in-chief is damaging to the office of the presidency, particularly on matters of foreign policy. “America is the leader of the world. Presidents need to speak on behalf of the country with one voice,” said Elaine Kamarck, a senior fellow in governance studies at the Brookings Institution. “This president doesn't care about continuity. He has a new view of America's role in the world, which is at odds with the views of his predecessors, including Republican presidents.” Obama has ignored the attacks Obama has never directly responded to Trump’s verbal attacks but has addressed the current president's approach to politics. In a speech two months ahead of the 2018 midterm elections, Obama said the current vitriolic political discourse “did not start with Donald Trump.” “He is a symptom, not the cause,” Obama said. “We are Americans. We’re supposed to stand up to bullies, not follow them.” Trump, a billionaire New York real estate investor, rose to prominence in national politics in part by promoting the “birtherism” conspiracy theory -- falsely claiming Obama was not born in the United States and therefore was not eligible for the presidency. Since taking office, Trump has worked systematically to dismantle much of Obama's legacy, including reforms in health care, climate change and immigration. “He sees the Obama administration as everything that was wrong with America prior to him, prior to President Trump coming into the White House,” said Jason Mollica, a lecturer at the school of communication at American University. Rallying Trump's base Mollica said Trump’s criticism of Obama helps rally the president's conservative base of voters heading into the 2020 election. “He knows the people that are for him, or maybe on the fence but leaning toward President Trump… will eat this up,” said Mollica. “They'll see this is great Twitter fodder, great social media fodder. This is wonderful for conservative outlets to continue to poke holes in the Obama business.” By continuing to bring up Obama, Trump is invoking the successful arguments he made while running for president in 2016, said Matt Dallek, a professor at The George Washington University Graduate School of Political Management. “It goes to some of the core critiques that he had about Washington and why they were losing out on trade deals to China,” Dallek said. “It’s another kind of deflection and distraction.” Dallek noted that it's not unusual for presidents – and even presidential candidates – to draw attention to the problems left behind by their predecessors. “Usually they do it in a more elliptical way,” he said. “They're usually less vitriolic and less explicit than Trump is.” Republicans back Trump's tactics Congressional Republicans have largely supported the president’s criticism of Obama. In a June 2019 interview, ABC News’ George Stephanopoulos asked Trump if he believed Obama was behind the investigation into allegations the Trump campaign colluded with Russia during the 2016 presidential election. Trump responded, “He certainly must have known about it because it went very high up in the chain.” This past week, South Carolina Senator Lindsey Graham echoed those concerns, telling Fox News’ Sean Hannity, “I can't imagine an investigation of the Republican nominee for president — a counterintelligence investigation of his campaign — was not approved at the highest level.” Trump has now served in office for more than two-and-a-half years. As the nation moves deeper into the 2020 election cycle, he will have to account for the successes and failures of his first term. He failed to repeal Obamacare – one of the former president’s signature legislative achievements and a continual target of his own attacks – even with control of both chambers of Congress in 2017 and 2018. Past presidents have shown restraint Mollica noted that past presidents have shown restraint in criticizing or upstaging their predecessors. For example, when Obama learned that U.S. forces had killed 9/11 mastermind Osama bin Laden May 1, 2011, the first person he called was former President George W. Bush, before the news was released. “President Obama could have easily criticized George W. Bush, saying you did not get Osama Bin Laden, we got him,” Mollica said. “It wasn’t about that. It was about the fact that we got the person who quote unquote was responsible for 9/11.”\n\nInstead, Bush was one of the first people to publicly congratulate Obama. Trump is unlikely to let up on his criticism anytime soon, particularly with Obama’s former vice president, Joe Biden, leading the field of 2020 Democratic presidential candidates. If Biden secures the nomination, Trump could directly connect his attacks on Obama with the battle to secure a second term. Experts told VOA Trump’s behavior is unique to him and unlikely to have a long-term impact on the presidency. “This is just one more aspect of President Trump's personality that is not at all likely to be repeated by subsequent presidents,” said Kamarck. “And for good reason. Most presidents seek to build bridges across parties to get things done. This president has never thought to do that, and to his detriment. It's not a very successful strategy.”