Vermont Sen. Bernie Sanders addressed the Democratic National Convention Monday to once again support his former opponent Hillary Clinton despite being booed earlier in the day for telling his supporters to vote for her. Hours later, they were detained by police while protesting outside the convention.

The former presidential candidate endorsed Clinton earlier this month, saying he would do everything to ensure she was the Democratic nominee. Sanders also likened GOP presidential candidate Donald Trump to a dictator after Trump's RNC speech. A press release from Sander's camp said that in his DNC speech, he would "make it clear that Hillary Clinton is by far superior to Donald Trump on every major issue from economics and health care to education and the environment."

We have got to defeat Donald Trump and do everything we can to elect Hillary Clinton to the White house. #DemsInPhilly

— Bernie Sanders (@BernieSanders) July 25, 2016

Sanders is hoping to reach out to the 13 million voters that supported him after several controversial days in the Democratic Party. Recently leaked email conversations among Democratic National Committee officials revealed it had been treating Sanders unfairly for months. One of those officials, DNC Chair Debbie Wasserman Schultz, stepped down from her post after the DNC.

In his speech, Sanders came out strongly in support of Clinton. "Hillary Clinton must become the next president of the United States," he said. "The choice is not even close." His speech, which you can read here and view above, talked about Clinton's progressive positions on issues like education, climate change, and health care.

Sanders said he and Clinton "have come together on a proposal that will revolutionize higher education in America." According to Sanders, any family that earns $125,000 a year or less will be able to send their children to a public college for free.

He added that Clinton was dedicated to combating climate change: "Hillary Clinton understands that a president’s job is to worry about future generations, not the short-term profits of the fossil fuel industry."

Sanders ended his speech by acknowledging that while he and Clinton had their disagreements during the primary campaign, he was strongly backing her now.

"I have known Hillary Clinton for 25 years," he said in summation. "I remember her, as you do, as a great First Lady who broke precedent in terms of the role that a First Lady was supposed to play as she helped lead the fight for universal health care. I served with her in the United States Senate and know her as a fierce advocate for the rights of children, for women, and for the disabled. Hillary Clinton will make an outstanding president and I am proud to stand with her here tonight."

Many Sanders supporters—and even some political opponents—were impressed by the speech.

Sanders pal Killer Mike was hopeful that the Clinton campaign would follow through with the policy positions Sanders laid out in his speech.

Some on the left were let down, however. The anti-war organization Code Pink, which infiltrated the RNC last week, called Sanders' speech "disappointing."

You can follow the DNC with the Complex News live stream, here.