Senator Bernie Sanders dominated tonight’s ABC News Democratic debate, sticking to the key issues facing America.

Throughout the debate, Senator Sanders was the most-discussed candidate on both Facebook and Twitter.

The debate started with Sanders apologizing for one of his staffers accessing Clinton’s campaign data, and the issue was dealt with fairly rapidly.

Terrorism, the fight against Islamic State and gun control were the primary focus in the first half of the debate.

On gun control, Senator Sanders identified himself as one of the 77 per cent of Americans who think the government cannot protect against lone-wolf terrorist attacks.

“I think we have got to bring together the vast majority of the people who do in fact believe in sensible gun legislation,” he said.

“Who denies that it is crazy to allow people to own guns who are criminals or are mentally unstable?” Sanders said to applause.

“There is a broad consensus on sensible gun safety legislation.”

It's time to strengthen gun safety laws: ✅Universal background checks ✅Assault weapon ban ✅Stricter gun trafficking laws #DebateWithBernie — Bernie Sanders (@BernieSanders) December 20, 2015

“We can do all the great speeches we want, but you ain’t going to succeed unless there is a consensus,” Sanders said to Martin O’Malley on gun control.

Sanders was asked why he doesn’t support United States combat troops joining a coalition to fight Islamic State.

“The United States of America cannot succeed or be thought of as the police of the world,” Senator Sanders said.

“This is a war for the soul of Islam. The troops on the ground should not be American troops, they should be Muslim troops.”

Sanders said that Qatar was spending $200 billion on the 2022 soccer World Cup, but very little on the fight against Islamic State, a point which was echoed on his Twitter account.

Qatar will spend $200 billion on the 2022 World Cup – $200 billion a soccer event, yet very little to fight against ISIS. #DemDebate — Bernie Sanders (@BernieSanders) December 20, 2015

Senator Sanders contrasted his foreign policy views with Hillary Clinton’s.

“I worry too much that Secretary Clinton is too much into regime change, and a little bit too aggressive without knowing what the unintended consequences would be,” Sanders said.

“I think yeah, regime change is easy, getting rid of dictators is easy, but before you do that, you’ve gotta think about what happens the day after.”

“The United States is not the policemen of the world,” Sanders finished as the moderators moved away from terrorism and into the real issues facing the United States.

The second half of the debate started without Clinton, who was back stage. As Sanders was being asked how he would raise incomes for middle-class families, Secretary Clinton walked onto the stage to applause, leaned into the microphone and said, “Sorry.”

“We recognize that we have a rigged economy,” Sanders began.

Equal pay for equal work. It’s not a radical idea. #DebateWithBernie — Bernie Sanders (@BernieSanders) December 20, 2015

Sanders said that millions of Americans are working longer hours for lower wages. He said that he would raise the minimum wage, close the wage gap between men and women, and invest $1 trillion in infrastructure to create 13 million new jobs.

“It is imperative that we have the best education workforce in the world.”

After Secretary Clinton was asked why corporate America loves her, Sanders was asked whether corporate America would like him. He said they would not, and used the issue to slam financial institutions and Wall Street.

“I don’t think I’m going to get a whole lot of campaign contributions from Wall Street. I don’t have a Super PAC. I don’t want contributions from corporat America,” he said.

“The greed of the billionaire class, the greed of Wall Street, is destroying this economy,” he said, and called for an economy that works for “all of us” and not just a handful of the powerful few.

You can’t take on Wall Street banks and billionaires by taking their money. #DebateWithBernie — Bernie Sanders (@BernieSanders) December 20, 2015

Sanders’ campaign was quick to send out a rapid “fact check” email to the media, which stated that Hillary Clinton has raised $29.2 million from the PACs and employees of banks, hedge funds, securities firms and insurance companies since the year 2000.

“So far, donors in the banking and insurance industries have given $6.4 million to her campaign and allied super PACs, behind only those in communications and technology,” the email from Sanders’ campaign read.

Sanders was quick to jump in after Secretary Clinton invoked his name.

“I helped lead the effort against Alan Greenspan, against a guy named Bill Clinton, against the Republican leadership, who all thought it would be a great idea to merge investor banks and commercial banks,” Sanders said.

“Wall Street is a threat to the economy that has got to be broken up.”

The debate moved to health care, and the moderator, Martha Raddatz, pointed out that Sanders supported a single-payer system.

“Not only are deductibles rising, 29 million Americans still have no health insurance, and millions of people can’t afford to go to the doctor,” Sanders said.

“Why is it that the Uunited States of America is the only country in the world today that does not guarantee health care to its people as a right?” he asked.

“We need to pass a Medicare-for-all single-payer system.”

Bernie Sanders’ Communicators Director, Michael Briggs, was quick to email the media to point out that families would save thousands under Sanders’ health care proposal.

I don’t think it’s a radical idea that in the richest country in the history of the world health care should be a right, not a privilege. — Bernie Sanders (@BernieSanders) December 20, 2015

Sanders was asked how free public college tuition would help the United States, when “taxpayers” would be footing the bill.

“This is the year 2015. If we are going to competitive in the global economy, we need the best educated workforce.”

He said that too many Americans cannot afford to go to college, and called for a tax on Wall Street speculation to pay for free public college. He also committed to lowering student loan interest rates.

“Now this is getting fun,” Sanders said as Clinton interrupted the debate moderator as he was attempting to ask about taxation.

Senator Sanders used the opportunity to call for paid family and medical leave. Martin O’Malley said he agreed with Sanders on paid family leave, and his proposal to expand social security.

“When a husband can’t get time off to care for his cancer-stricken wife, that is not a family value,” Sanders’ campaign tweeted.

'Socialist' programs from FDR and LBJ: ✅Social Security ✅Minimum Wage ✅Medicare and Medicaid ✅40-hour work week #DemDebate — Bernie Sanders (@BernieSanders) December 20, 2015

The debate went into a break, before it entered its final segment. Sanders was asked how he would bridge the divide between civilians and law enforcement.

“Let’s be clear. Today in America, we have more people in jail than any other country on earth. 2.2 million people, predominately African-American and Hispanic. We are spending $80 b a year locking up our fellow Americans

“We need to make a major effort to come together as a country and end institutional racism.”

“Police officers should not be shooting unarmed people. predominately African-Americans,” Sanders said to apllause.

Sanders addressed the need to end the ‘War on Drugs’ and move toward community policing, to look like the communities that they served. He also called to end minimum sentencing.

Senator Sanders was asked about the heroin epidemic. He said that addiction is a disease, not a criminal activity.

“When somebody is addicted and seeking help, they should be able to walk in the door tomorrow and get a variety of treatments for them,” he said.

Addiction is ravaging families and communities in NH. This is a crisis, and we need to treat it as a health issue—not throw people in jail. — Bernie Sanders (@BernieSanders) December 20, 2015

Secretary Clinton was asked how much responsibility she bears for the situation in Libya, and she was pushed hard on that issue by Martha Raddatz.

“This is a terribly complicated issue,” Senator Sanders said when it was his turn to discuss the issue.

Sanders said that it is easy for the United States to overthrow a dictator, but it is hard to predict the consequences. He said that Secretary Clinton is a bigger fan of regime change than he is.

Towards the end of the debate, the moderators asked about changing the role of the president’s spouse. Sanders was asked whether his wife, Jane would have a desk close to the Oval office. He said that she would because she is ‘much smarter’ than he is. The two share a desk and Sanders’ campaign headquarters in Burlington, Vermont.

He said he thinks his wife would do a fantastic job in achieving his goals as president.

The debate took its final commercial break for the evening, before candidates made their closing statements.

In his closing statement, Sanders said his Democratic colleagues, on their worst day, have more to offer than right-wing Republicans on their best day.

“I know something about economic anxiety, and living in a family that does not have sufficient income. That is why I am pledged, if I am elected President of the United, to bring about a political revolution,” he said.

“This country belongs to all of us. Not just a handful of billionaires.”