Martin Luther King Jr. understood the moral authority that is earned by the willingness to suffer for your cause without retaliation, to take your beating and jail time and then get up the next morning and have the courage to do it again, to risk your life again.

King also knew that his strategy was made more effective by the disproportionate response it provoked from those in authority. Peaceful marchers for the right to vote, for example, were often met with police dogs and firehoses. Through that overreaction, those in power weakened themselves and exposed who they really are.

John Lewis, one of King’s lieutenants, has not forgotten those lessons. The Atlanta congressman announced Friday that he would boycott the inauguration of Donald Trump because, he said, he did not view Trump’s election as legitimate after revelations of intervention by Russia.

Ordinarily, that would be a story with a media lifecycle of a few hours. But as surely as night follows day, Trump responded disproportionately, attacking Lewis personally and describing his Fifth Congressional District as “burning and crime-infested … in horrible shape … falling apart.”

So once again, Trump shows that he is at heart a little man. He knows it, and his greatest fear is that others see it too. Have you known anyone in your adult life who whines more than Trump does, who yelps like a kicked dog at every perceived slight? As the old saying goes, he can dish it out but he sure can’t take it.

As it happens, I live in the Fifth District. We’ve made our home here for more than a quarter century and raised our family here, and I do not recognize the picture that Trump draws of this place. In Trump’s mind, Lewis is a black congressman so of course his district must be burning and crime-infested. The idea that Lewis’s district is actually the economic engine of the South, with more than 40 percent of its population possessing college degrees and the landscape dotted with construction cranes, is beyond Trump’s comprehension because it contradicts the racist stereotypes by which he lives.

Lewis’s boycott has provoked responses from other Republicans as well. Gwinnett County Commissioner Tommy Hunter felt inspired to call Lewis “a racist pig” in a Facebook rant, and Trump’s White House chief of staff, Reince Priebus, went on TV to call it “shocking” and “insanity” and “incredibly disappointing” for Lewis to question Trump’s legitimacy as president. He even called upon President Obama to intervene with Lewis and his fellow Democrats, to “step up and get his people in line.”

I keep thinking I can’t be amazed by this stuff any longer, that I can’t still be startled by the ability of people such as Priebus to utter such garbage with a straight face. I keep being wrong. Through his birther nonsense, Trump built his popularity among the Republican base by directly and repeatedly attacking Obama’s legitimacy not just as president but as an American, yet Priebus now expects us to just wipe that from our memory.

And when Priebus himself was asked about birtherism back in 2011, the then-chairman of the GOP didn’t “get his people in line,” as he now demands of Obama. He said that Trump and other candidates “can talk about it all they want” as far as he is concerned. That’s the kind of courage that he showed at the moment that it mattered. All talk, no action.