We shouldn’t be surprised anymore.

There’s apparently no depth too low for Donald Trump to sink in his unpresidented attacks on anyone who challenges him. And Rep. John Lewis (D-Ga.) certainly did that, citing Russian interference in the election and questioning the legitimacy of Trump’s presidency.

Even so, the president-elect’s Twitter tirade against Lewis at the beginning of the Martin Luther King Jr. holiday weekend is still mind-boggling and a national embarrassment.

Trump called Lewis, who risked his life to defy segregation, who has been arrested 40 times for his unrelenting activism, who helped get voting rights for millions of Americans, who kept fighting even after his skull was fractured, “All talk, talk, talk — no action.”

So let’s compare Trump’s actions to Lewis’s actions.

(Ashleigh Joplin,Randolph Smith,Rhonda Colvin/The Washington Post)

We can start in 1960, when Trump was 14 and Lewis was 20. They both clearly showed their leadership potential early.

At New York Military Academy in Cornwall, N.Y., Donald Trump won a “neatness and order medal.”

That same year, John Lewis became one of the original 13 Freedom Riders, defying laws that prohibited blacks and whites from sitting next to each other on public transportation.

Three years later in 1963, man-of-action Trump led his private school’s white-gloved drill team in the Columbus Day parade in New York. But he was also removed from that drill team command, classmates said, because he hazed younger students.

That same year, Lewis helped organize the March on Washington for Jobs and Freedom and spoke alongside the Rev. Martin Luther King Jr. on the steps of the Lincoln Memorial.

In 1965, Trump got his second Vietnam draft deferment as a Fordham University student.

In 1965, on a day that became known as Bloody Sunday, Lewis helped lead 600 marchers across the Edmund Pettus Bridge in Selma, Ala. When the marchers stopped to pray, they were tear-gassed and beaten by troopers. Lewis’s skull was fractured.

1 of 33 Full Screen Autoplay Close Skip Ad × These Democratic lawmakers are boycotting Donald Trump’s inauguration View Photos They say they are declining to attend in protest of the president-elect’s worldview and his criticism of civil rights icon John Lewis, a congressman from Georgia. Caption They say they are declining to attend in protest of the president-elect’s worldview and his criticism of civil rights icon John Lewis, a congressman from Georgia. Rep. Don Beyer (D-Va.) Beyer tweeted: “I just told hundreds of my constituents that I will not be attending the Inauguration Ceremony this coming Friday.” John McDonnell/The Washington Post Buy Photo Wait 1 second to continue.

In 1973, Trump’s actions got him sued by the Department of Justice. He was managing his dad’s properties and wouldn’t rent apartments to African Americans. The Trumps eventually settled the lawsuit without any admission of wrongdoing.

That same year, John Lewis was running the Voter Education Project, which pushed to register minority voters across the country.

Trump owned the ’80s, right? His actions that decade?

In 1981, Trump bought a 14-story building facing New York City’s Central Park and began a campaign to drive out the rent-stabilized tenants so he could begin gutting and renovating the building. According to lawsuits, Trump cut heat and water to the remaining tenants.

In 1981, John Lewis was elected to the Atlanta City Council.

In 1987, Trump’s book, “The Art of the Deal,” became a bestseller. Action? He didn’t even write it; talk about talk talk talk. And his ghostwriter, Tony Schwartz, now regrets the picture he painted of Trump in that book.

In 1987, Lewis was elected to Congress.

I don’t think Trump knows enough about America or American history to have deliberately targeted one of our country’s civil rights heroes in his tweet storm.

You can see that in his messages: “Congressman John Lewis should spend more time on fixing and helping his district, which is in horrible shape and falling apart (not to mention crime-infested).” Much of Lewis’s district is affluent. But Trump demonstrated again that he equates black people with crime.

So there was hope last week when it was announced that he was going to visit the National Museum of African American History and Culture on Martin Luther King Day. It looked as though he may have been willing to fill in some of the gaps in the American story he’s been missing, including the part Lewis played in the triumphs of the civil rights movement.

But then Trump canceled the visit. Turns out it was all talk, talk, talk.

Twitter: @petulad