President Donald Trump to go after his predecessor Friday just 1 minute, 9 seconds to reengage in a debate that has consumed much of his own time in office over who was the better president.

It was former President Barack Obama who started the policy of separating children from their parents at the border, Trump claimed falsely, and it was Obama who had such a terrible relationship with North Korea that he was about to go to war. Obama had it easy on the economy, Trump added, but let America’s allies walk all over him.

The president’s focus on Obama after about 2 1/2 years in office was even more intense during a trip to Japan and South Korea last weekend, when Trump repeatedly raised the subject of his predecessor without being asked, assailing him on a variety of domestic and foreign policy fronts.

In part, that reflects Trump’s long-standing fixation with the former president. But it may also stem from the fact that Obama’s vice president, Joe Biden, remains the Democratic front-runner in the 2020 election.

“If you look at what we’ve done, and if you look at what we’ve straightened out, the I call it the ‘Obama-Biden mess,’” he told reporters on the South Lawn of the White House before leaving Washington for a weekend at his golf club in Bedminster, New Jersey. “We’re straightening it out.”

“When in a corner, Trump falls back on the only organizing principle he has, which is attacking Obama and usually lying about it,” said Benjamin Rhodes, a former deputy national security adviser to Obama. “I wouldn’t read anything more into it than that.”

He repeatedly questioned Obama’s citizenship as part of the false “birther” conspiracy. As president, Obama struck back at the White House Correspondents’ Association dinner in 2011, when he roasted the reality television star as a lightweight while Trump sat grim-faced.

Since then, Trump has been determined to minimize or unravel Obama’s accomplishments and lately has even suggested that his predecessor was behind a deep-state conspiracy with law enforcement and intelligence agencies to thwart his 2016 candidacy.

While other presidents have blamed their predecessors for various national ills including Obama, who in his first term regularly pointed to former President George W. Bush Trump takes it further than most.