While not directly naming the candidate, President Obama made it clear just what he thinks about Donald Trump's campaign and policy proposals in a highly political commencement speech Sunday at Rutgers University.

The president said he would skip giving students the usual commencement banter, and instead run down a list of "suggestions" that turned out to be a stern and direct indictment of everything Trump has built his campaign on.

First, Obama took on Trump's "Make America Great Again" campaign slogan, telling students, "When you hear someone longing for the good old days, take it with a grain of salt."

Obama told graduates that despite what they may hear on the campaign trail, he believed they were better positioned than at any time to succeed and said the reason America doesn't tend to move backwards is "because you don't fear the future."

Obama then went directly after Trump's proposals to build a wall at the U.S.-Mexico border, and to ban Muslims from entering the country.

"The world is more interconnected than ever before, and it's becoming more connected every day. Building walls won't change that," Obama said. "Isolating or disparaging Muslims, suggesting they should be treated when they come to this country, that is not just a betrayal of our values -– that's not just a betrayal of who we are –- we alienate the very communities at home or abroad who are our most important partners in the fight against violent extremism.

"Suggesting that we can build an endless wall along our borders and blame our challenges on immigrants, that doesn't just run counter to our history as the world's melting pot, it contradicts the evidence that our growth, and our innovation and our dynamism has always been spurred by our ability to attract strivers from every corner of the globe," Obama continued. "It's how we became America, why would we want to stop it now?"

Obama then took aim at what he called a "strain of anti-intellectualism" in American politics, saying, "in politics and in life, ignorance is not a virtue."

"It's not cool to not know what you're talking about," Obama said. "That's not challenging political correctness, that's just not knowing what you're talking about."

He then called out leaders who are allowed to promote "the wildest conspiracy theories," who "express a disdain for facts" and then are "not held accountable."

Near the close of his speech, there was also a seeming slight at the campaign message of Bernie Sanders, as Obama belied those who exaggerate the corrupt and "rigged system," saying the great changes in American history "didn’t happen because some massive political revolution occurred."

"Contrary to what we hear sometimes from both the left as well as the right, the system is not as rigged as you think and it certainly is not as hopeless as you think," Obama said.