The most venerable schoolyard response from a child caught behaving badly is becoming a fixture in the Trump era of American politics.

“Yeah, but what about him ... or her?” points the child offender.

There is a term for this tactic of manic and often disingenuous deflection: “whataboutism.”

President Trump neither invented nor perfected whataboutism as a propaganda tool to suggest one regime is no worse than any other. That credit goes to — who else? — the Soviet Union during the Cold War, when any challenging of its jailing of dissidents or other human rights violations would lead to a retort about racism, police brutality or foreign intervention by Americans.

The “whataboutism” rhetorical device was resurrected big time by — who else? — Russian President Vladimir Putin. When asked about the Russian annexation of Crimea, for example, Putin in 2014 naturally cited the U.S. seizure of Texas from Mexico in 1845 (after a plebiscite, it must be noted). The 2003 U.S. invasion of Iraq is often invoked by Russia to rationalize its military adventures.

The American president who has uttered nary a discouraging word about his Russian counterpart seems to have a Putin-like reflexive penchant for whataboutism.

In fact, Trump even used the tactic in defense of Putin in a February interview with Bill O’Reilly on Fox News.

“Putin’s a killer,” O’Reilly observed, asking Trump how he could respect the authoritarian leader.

“There are a lot of killers,” Trump whatabouted. “We’ve got a lot of killers. What do you think — our country’s so innocent?”

Putin had to have been smiling.

More recently, while feeling the heat about his tepid response to the white supremacists’ show of clench-fisted bigotry in Charlottesville, Va., Trump came back with a succession of whatabouts.

“What about the alt-left that came charging at the, as you say, the alt-right? Do they have any semblance of guilt?” Trump said, employing one of the defining traits of whataboutism: false equivalency, as if the provokers of a fight were no more responsible for the conflict than those who came to denounce the demonstration of hate.

Trump came prepared with a whatabout list when reporters started peppering him with questions about his pardoning of Joe Arpaio, the former Arizona sheriff who had been convicted of defying a judge’s order to stop wantonly profiling Latinos as suspected of being in the U.S. illegally. As usual, most roads lead to a Clinton and former President Barack Obama.

“I want to look at some of the other people who were pardoned over the years,” Trump said, rattling off a succession of his Democratic predecessors’ actions.

Trump’s apologists on cable news have taken his cue on how to counter criticism of him. The talking points have become all too predictable.

Mention a Trump lie: “What about President Obama saying ‘You can keep your doctor’ in Obamacare?”

Mention how Trump and his family are using his position for enrichment. “What about donations to the Clinton Foundation and Bill and Hillary’s speaking fees?”

Mention any disclosure embarrassing to Trump: “What about the illegal leaks?”

Mention the media or congressional focus on Trump campaign collusion with Russia: “What about the Clinton emails?” “What about the Debbie Wasserman Schultz scandal?” Or if all else fails, “What about Benghazi?”

Some commonly spread pro-Trump whatabouts are just plain fake news. Kayleigh McEnany, one of Trump’s more aggressive surrogates on cable news before she became a spokeswoman for the Republican National Committee, defended the president’s excessive time on the links by claiming Obama “rushed off to a golf game” after journalist Daniel Pearl was beheaded by terrorists after being abducted in Pakistan. Pearl was killed in 2002 — while Obama was an Illinois state senator. She apologized.

Social media hummed with Trump apologists, bristling at criticism of his Hurricane Harvey response, “noting” that Obama went golfing in the wake of Hurricane Katrina. That was in 2005, more than three years before the U.S. senator became president. Obama, in fact, did go to Houston to meet with Katrina evacuees.

To be fair, hyper-partisan supporters of any politician have resorted to whataboutism since the time of original sin. Obama defenders were often quick to favorably compare his administration to the miscalculations and faults of President George W. Bush, and Bush’s defenders pointed to the same about President Bill Clinton.

The distinction between the Trump era and the past is that presidents themselves have generally refrained from such cheap rhetorical tactics. Trump has exhibited no such restraint.

Trump already has given his successors plenty of material for whataboutisms. A future president who strikes out on legislative achievements, fails to denounce racists and dictators, routinely spews falsehoods and vitriol on Twitter, or fires those who are determined to investigate official wrongdoing just might be tempted to say ... “What about Trump?”

Our nation’s leaders should aspire to the highest achievements of their predecessors, instead of excusing their shortcomings by citing the perceived failings of others.

John Diaz is The San Francisco Chronicle’s editorial page editor. Email: jdiaz@sfchronicle.com Twitter: @JohnDiazChron

Practiced at the art of deflection

President Trump frequently responds to criticism by pointing to faults of others: