Who is the most divisive figure in American politics, Donald Trump or Barack Obama? It's the question at the heart of the 2016 presidential race.

As Trump's campaign rallies increasingly degenerate into fisticuffs, fingers are pointing over who's to blame. One rally participant sucker punched an African-American protestor. The billionaire's big Chicago event before the Illinois primary was canceled due to security concerns.

Trump clearly bears some responsibility for encouraging an atmosphere at his campaign events that resembles professional wrestling more closely than presidential politics. Shouting down protestors and sometimes removing them by force has become a major part of his shtick on the stump. "Get 'em out of here," Trump says from the podium as the offenders are escorted out of the venue by security. He has favorably compared his strength in dealing with protests to the weakness of presidential candidates such as Bernie Sanders.

The people who disrupt campaign events are also responsible for their actions. Since many have been Bernie Sanders supporters, the Vermont senator has had to deny having anything to do with the chaos. "Obviously, while I appreciate that we had supporters at Trump's rally in Chicago, our campaign did not organize the protests," Sanders said. "What caused the protests at Trump's rally is a candidate that has promoted hatred and division against Latinos, Muslims, women and people with disabilities, and his birther attacks against the legitimacy of President Obama."

Donald Trump clearly bears some responsibility for encouraging an atmosphere at his campaign events that resembles professional wrestling more closely than presidential politics. (AP Photo)

The Republican establishment can't be let off the hook. Despite promising every two-four years that the country faces the most important election in its history, long-term conservative goals on abortion, school prayer, the size of the federal government and securing the border remain unrealized. Even more recent innovations, ranging from Obamacare to the administration's executive actions, feel permanent. Rank-and-file conservatives feel their elected officials always lose their fights with the White House.

But what about the broader climate of anger and division that has made Trump's status as the front-runner for the Republican nomination possible in the first place? It's very different from the atmosphere President Obama promised when he was a candidate for the office in 2008.

"The politics of resentment against other people will not just leave us a fractured party, they are going to leave us a fractured nation," Marco Rubio said as he exited the presidential race last week. "They are going to leave us as a nation where people literally hate each other because they have different political opinions."

If there was any confusion about whether Rubio was referring to Trump's campaign events, when a heckler interrupted his concession speech, the Florida senator quipped, "Don't worry, you won't get beat up at our event."

"I'm not the only one in this room who's more than a little dismayed about what's been happening on the campaign trail recently," Obama told lawmakers on Capitol Hill, adding that the culprit driving the violence is "vulgar and divisive" rhetoric directed at those who "don't look like us or pray like us or vote like we do."

"I'm not the only one in this room who's more than a little dismayed about what's been happening on the campaign trail recently," Obama told lawmakers on Capitol Hill. (AP Photo)

Yet others suggest Obama should look in the mirror. The Wall Street Journal editorial page declared that the president's rhetoric "helped fuel [Trump's] ascent," specifically criticizing Obama for appearing to believe "principled opposition to his policies is always illegitimate or motivated by bad faith."

"Like the president's nonstop moral lectures about 'our values' and 'who we are as Americans,' by which he means liberal values and who we are as Democrats, he reads his critics out of politics," the paper editorialized. "No wonder so many Americans feel disenfranchised and powerless."

Bobby Jindal, who unsuccessfully sought the 2016 GOP presidential nomination, took to the same page to argue that Obama deserves "credit for creating one of the most polarizing forces in American politics today."

"There would be no Donald Trump dominating the political scene today if it were not for President Obama," Jindal wrote, later adding that while the president "likes to bemoan the increasing partisan divides across the country, as if he was merely a passive observer at best and a victim at worst," Obama "created the very rancor he now rails against."

New York Times conservative columnist Ross Douthat, a frequent Trump critic and early skeptic of the billionaire's ability to win the nomination, nevertheless called the New York businessman "a creature" of the president's second term.

"President Obama didn't give us Trump in any kind of Machiavellian or deliberate fashion," Douthat wrote. "But it isn't an accident that this is the way the Obama era ends — with a reality TV demagogue leading a populist, nationalist revolt."

In short, Obama gathered the tinder. Trump lit the match.

The president doesn't see things that way. "I'm not going to validate some notion that the Republican crackup that's been taking place is a consequence of actions that I've taken," he said, urging GOP "introspection."

"I don't think I was the one to prompt questions about my birth certificate, for example," Obama continued. "I don't recall saying, 'Hey, why don't you ask me about that. Why don't you question whether I'm American or whether I'm loyal or whether I have America's best interests at heart?'"

But the president did choose to take sides in a number of deeply polarizing controversies even as he presented himself as above the fray, sometimes without much obvious investigation of the facts at hand. When his friend, the African-American Harvard professor Henry Louis Gates, was arrested for disorderly conduct in 2009 after someone reported a possible burglary in progress as he tried to force his way through a jammed door (the charges were dropped), Obama said the police "acted stupidly" and turned the incident into a parable about racial profiling.

"I don't know, not having been there and not seeing all the facts, what role race played in that," Obama said. "But I think it's fair to say, number one, any of us would be pretty angry; number two, that the Cambridge police acted stupidly in arresting somebody when there was already proof that they were in their own home; and, number three, what I think we know separate and apart from this incident is that there's a long history in this country of African-Americans and Latinos being stopped by law enforcement disproportionately."

The president admitted to not knowing the facts, but then immediately and definitively took a side while opining on the motives of the police. A resolution was introduced in the House calling on the president to apologize and one poll showed 41 percent of the American public disapproved of how he handled the situation while only 29 percent approved. The law enforcement backlash was predictable, and Obama had to backtrack.

"I want to make clear that in my choice of words I think I unfortunately gave an impression that I was maligning the Cambridge Police Department or [arresting officer] Sgt. Crowley specifically — and I could have calibrated those words differently," Obama said two days after his initial comments. "I continue to believe, based on what I have heard, that there was an overreaction in pulling Professor Gates out of his home to the station. I also continue to believe, based on what I heard, that Professor Gates probably overreacted as well."

As Trump's campaign rallies increasingly degenerate into fisticuffs, fingers are pointing over who's to blame. (AP Photo)

The president, professor and police officer all joined Vice President Joe Biden for a White House "beer summit" to discuss the incident and treat it as a "teachable moment," which ended the controversy. But it served as a template for future incidents where instead of acting as a calming presence when the public was divided, the president exacerbated the divisions by weighing in on one side even when the facts were ambiguous or still unsettled.

More recently, there was the case of 14-year-old Ahmed Mohamed, who brought a clock to his Irving, Texas, school that his teacher thought resembled a bomb. He was arrested but ultimately released and never charged with anything. Mohamed's arrest was condemned as an example of racial profiling and anti-Muslim paranoia.

The facts were still being determined, but the president wasted no time weighing in on the incident. "Cool clock, Ahmed," Obama tweeted from his official account hours after the arrest. "Want to bring it to the White House? We should inspire more kids like you to like science. It's what makes America great." He received over 400,000 retweets.

The attorney general of the United States also vowed the Justice Department would investigate. "When we are ruled by fear," Loretta Lynch said, "we are not making ourselves safe." Mohamed's family demanded an apology and $15 million from the city.

Many conservatives complain that Obama implicitly impugns the character of his critics while moving to preemptively shut off debate. Former Virginia Republican official Kate Obenshain wrote a book calling Obama the Divider-In-Chief, arguing he "needs to avoid the messiness of debate and replace it with divisive identity politics to pass his agenda."

Obama has acknowledged failing to heal the country's divisions as promised in his 2004 Democratic National Convention speech chastising the "pundits" for their tendency to "slice and dice our country into red states and blue states." But he attributes Trump's rise and the angry political culture solely to Republicans and conservative media.

"[O]bjectively, it's fair to say that the Republican political elites and many of the information outlets, social media, news outlets, talk radio, television stations have been feeding the Republican base for the last seven years a notion that everything I do is to be opposed, that cooperation or compromise somehow is a betrayal, that maximalist, absolutist positions on issues are politically advantageous, that there is a them out there and an us, and them are the folks who are causing whatever problems you're experiencing," Obama said in lengthy public comments on the subject.

President Obama has chosen to take sides in a number of deeply polarizing controversies even as he presented himself as above the fray. (AP Photos)

A Republican strategist who advised Rubio shot back on Twitter, "We'll take responsibility for our party, but he has to accept responsibility for our country."

When Obama can't persuade Congress to adopt his agenda, he boasts of what he can do with a "pen and a phone." His executive actions on guns and immigration made activists who disagree with him feel helpless; the latter stretches the bounds of the legal limits of his power and has been contested in court.

Congressional Republicans haven't been eager to work with Obama, although some of this hesitancy is due to sincere policy disagreements and not just political opportunism. But it is a two-way street. The president doesn't have close relationships with GOP leaders (or Democratic ones, for that matter). He often presents his plans as if they are a fait accompli and openly describes the other party as "hostage takers" with whom he refuses to negotiate.

Republicans on Capitol Hill can either adopt his proposals on climate change and gun violence, or they can, he argues, reveal they don't care about the underlying problems due to ignorance, ideological rigidity or fealty to nefarious forces such as the NRA or the Koch brothers. This kind of rhetoric does not instill a spirit of bipartisan cooperation. It goes to motive. It is the classic device of the low debater on Internet comment boards — any who disagrees is a fool or a knave. If you say that sort of thing, you tend to cause bitterness.

The president is inclined to rub opponents' faces in their defeat. When the Supreme Court ruled that gay marraige was a constitutional right, it was a heavy defeat for that very substantial minority that still believed marriage is the union of one man and one woman. Given that he claimed to believe this himself until shortly before the 2012 election, Obama might be expected to have shown some understanding and sympathy for the pain of those who had not flipped, or evolved, on the issue.He could have accepted the court decision with a quiet grace.

Yet, instead, his White House went into full gloat mode, bathing 1600 Pennsylvania Ave. in the rainbow colors of the gay rights movement. To traditionalists nationwide it was like being given the middle finger — and insult added to injury by a divisive president.

The arrest of 14-year-old Ahmed Mohamed, aka "Clock Boy", was condemned as an example of racial profiling and anti-Muslim paranoia. While the facts were still being determined, the president wasted no time weighing in on the incident. (AP Photo)

Democrats, too, feel some of this anger about the direction of the country under Obama, which is why Sanders has done better than expected in his socialist "revolution" against the party establishment. Sanders is losing to Hillary Clinton, but he draws big, young crowds on the stump and has won a number of primaries arguing that the financial and political system is rigged against the little guy. When you listen to the Vermont senator talk about the state of the economy, you would think he was describing the end of Herbert Hoover's administration rather than Obama's. Even progressives don't believe recent economic growth has been widely shared.

GOP consultant Liz Mair, who has been active in the movement to deny Trump the nomination, said it was a "tad simplistic" to blame Obama for the billionaire's political success and that a lot of his appeal can be more plausibly traced to economic anxieties. But she does believe Obama has contributed to the vacuum Trump is filling.

"He comes off as self-interested and aloof to a lot of people — whether they're Trump voters or Sanders voters," Mair said. "Whether one likes it or not, the fact is, he has at times done and said things that read as callous and uncaring, especially towards working-class white voters, and reads as a pretty stereotypical narcissistic big city elitist to a lot of the country.

"Second, from a policy perspective, he took over from another guy who didn't deliver for a lot of these voters, and under whose tenure they either lost ground in terms of their family's economic security, or simply wound up in a situation of economic stasis (by the way, that guy deserves blame, too)," she added. "Obama didn't fix it — or at least, he didn't fix it for them."

"Look, we've been a divided country since that famous red and blue map made its television debut in 2000," said another consultant who has worked on Democratic campaigns. "Obama hasn't fixed it and doesn't know how, but guys like Trump try to exploit it for their own purposes."

As Obama's second term comes to a close, exploiting division may be the one thing that unites politicians across the spectrum.