Barack Obama is no fan of Trump and has made it clear enough in a number of his speeches in which he has criticised the front-running presidential candidate. Addressing Rutgers University's class of 2016 at the school's 250th anniversary commencement on 15 May, the US president opted not to refer to Trump directly but took a number of swipes at the man himself and his political campaign proposals.

Speaking to a crowd of more than 50,000 students, faculty and guests, Obama urged them to turn away from politics that works to divide rather than unify. "So class of 2016, let me be as clear as I can be: in politics and in life, ignorance is not a virtue," he told the audience. "It's not cool to not know what you're talking about. That's not keeping it real or telling it like it is. That's not challenging political correctness, that's just not knowing what you're talking about. And yet we've become confused about this."

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Describing what he called "anti-intellectualism" Obama pressed on, "The rejection of reason, the rejection of facts; that is the path to decline."

Targeting Trump's campaign slogan, Make America Great Again, he added, "When you hear someone longing for the good old days, take it with a grain of salt.

"The good old days were not all that good."

Dressed in a red and black robe, the POTUS then went on to discuss Trump's proposals for the Mexico border wall. "The world is more interconnected than ever before and it is becoming more connected every day. Building walls won't change things," he said. "Suggesting that we can build an endless wall along our borders and blame our challenges on immigrants, that does not just run counter to our history as the world's melting pot."

Moving onto a lighter subject, the president added, "The truth is, Rutgers, I came here because you asked," Obama said. "You are the first to launch a three-year campaign" that included emails, letters, tweets, YouTube videos and three letters from the student body president's grandmothers.

"That was smart," he said. "I have a soft spot for grandmothers."