Abandoning the precedent set by previous presidents, former President Barack Obama has consistently undermined his successor’s policy agenda and has spoken out against virtually all of the major pillars of President Donald Trump’s domestic policy agenda.

Again and again, Obama has publicly undermined Trump’s signature policy plans, on issues ranging from Trump’s proposed border wall to the Republican attempts to repeal and replace Obamacare.

Obama’s repeated public opposition to Trump stands in stark contrast to the example set by former President George W. Bush, who remained on the sideline during the Obama years. “I don’t think it’s good for the country to have a former president undermine a current president,” Bush explained in 2014.

Obama’s inner circle said during the transition that the former president wanted to extend that same courtesy to President Trump. “We now are going to want to do everything we can to help you succeed, because if you succeed, then the country succeeds,” Obama said to Trump in front of reporters following the election.

It didn’t last long.

Just 10 days into Trump’s presidency, Obama came out against Trump’s proposed travel ban from seven terror-prone countries, saying through a spokesman that he was “heartened” by liberal protests against the travel ban. White House counselor Kellyanne Conway warned at the time that Obama was playing a “dangerous game.” (RELATED: ‘Rank Hypocrisy’: Joe Scarborough Slams Obama’s Response To Travel Ban [VIDEO])

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Obama’s public opposition to the Trump agenda has only escalated since he came out against travel ban.

Trump’s travel ban marked the start of increasingly confrontational positions from Obama.

When Trump fulfilled his campaign promise of withdrawing the US from the Paris climate accords in June, Obama accused Trump of “rejecting the future” and leaving an “absence of American leadership.” While speaking in Indonesia a month later, Obama again criticized Trump’s decision to leave the Paris accords and appeared to be referencing Trump in warning against “an aggressive kind of nationalism.”

Obama has also taken shots at the defining policy of Trump’s presidential campaign: his plan to build a border wall along the US-Mexico border.

“In this new world we live in, we can’t isolate ourselves — we can’t hide behind a wall,” Obama said while speaking in Berlin in May. USA Today described Obama’s remark as sending Trump a “clear message.”

During the debate over attempts to repeal and replace Obamacare — which has been a Republican campaign theme for years and was a hallmark of Trump’s presidential campaign — Obama again spoke out.

When Senate Republicans unveiled their Obamacare replacement in late June, Obama trashed the legislation, saying it was “not a health care bill” but a “massive transfer of wealth from middle-class and poor families to the richest people in America.”

“Simply put, if there’s a chance you might get sick, get old, or start a family – this bill will do you harm. And small tweaks over the course of the next couple weeks, under the guise of making these bills easier to stomach, cannot change the fundamental meanness at the core of this legislation,” Obama wrote in a viral Facebook post, which was shared more than 330,000 times.

Obama unleashed his harshest criticism of President Trump on Tuesday, after Trump announced his administration would be gradually rolling back Obama’s Deferred Action for Childhood Arrivals (DACA) amnesty program, which was thought to be on shaky legal ground.

“To target these young people is wrong – because they have done nothing wrong. It is self-defeating – because they want to start new businesses, staff our labs, serve in our military, and otherwise contribute to the country we love,” Obama wrote. “And it is cruel.”