Analysis by Zachary B. Wolf, CNN

(CNN) -- President Donald Trump can't merely slur Elizabeth Warren with the nickname "Pocahontas" anymore. That's old hat.

To effectively torment and tease her, he now seems to feel compelled to throw in an allusion to shameful episodes from US history.

This weekend, it was a not-subtle allusion to the Trail of Tears -- the forced migration of American Indians from Mississippi to present-day Oklahoma -- to poke fun at Warren on the occasion of her official 2020 campaign kickoff.

Insensitive by design, Trump set the scene by calling Warren "Pocahontas" and then drove the point home with an all-caps, "See you on the campaign TRAIL, Liz" sneer.

Coincidence? Did he just accidentally capitalize those words? Hopefully not, since Trump should know this history. While the Obama administration sought to take Andrew Jackson off the $20 bill, Trump put a portrait of Jackson, whose Indian Removal Act led to the Trail of Tears in the 1830s, in the Oval Office.

And in case anyone didn't get the joke, his son Don Jr. shared it and added "Savage!!! I love my President."

The structure of this new Trail of Tears tweet was nearly identical to one from January in which he invoked Wounded Knee -- site of the massacre of Lakota Indians by the US military in 1890.

"If Elizabeth Warren, often referred to by me as Pocahontas, did this commercial from Bighorn or Wounded Knee instead of her kitchen, with her husband dressed in full Indian garb, it would have been a smash!," he tweeted then.

For her part, Warren suggested during an event in Iowa that Trump may "not be a free person in 2020." It's not exactly the "Lock Her Up!" chants Trump supporters used against Hillary Clinton in 2016, but it certainly gets at the point that a lot of Democrats think Trump's campaign colluded with the Russian government in 2016.

Trump's long campaign to bully Warren began years ago when he started calling her "Pocahontas," but it has intensified in recent weeks with these new tweets that dovetail with new scrutiny of when and how Warren claimed Native American background.

CNN political commentator Ana Navarro described these tweets as Trump's attempt to "trigger" Republicans.

"There is something about Elizabeth Warren that triggers Republicans, that triggers conservatives, that triggers the right wing." She said Ted Cruz has a similar effect on Democrats.

Warren won't be Trump's only target in 2020, however. And so this is where the nation finds itself; the President searching for increasingly inflammatory ways to bully a rival.

A day later he didn't slur Amy Klobuchar, the Minnesota Democrat who also announced a run over the weekend, but he did use her campaign announcement to question the underpinnings of climate change. Again.

"Well, it happened again. Amy Klobuchar announced that she is running for President, talking proudly of fighting global warming while standing in a virtual blizzard of snow, ice and freezing temperatures. Bad timing. By the end of her speech she looked like a Snowman(woman)!"

Climate change, as has been pointed out repeatedly this winter, does not mean there won't be snowstorms. Hopefully, Trump knows that at this point. It doesn't really matter, though, since he'll take any opportunity to tweet a jab, regardless of the seriousness of the issue.

Twitter jokes rarely blend with policy, and it is not just Trump who has seen a Twitter taunt fall flat.

Rep. Ilhan Omar, the freshman Democrat from Minnesota, faces backlash for her retweet of a comment by the activist/journalist Glenn Greenwald.

Greenwald said: "GOP Leader Kevin McCarthy threatens punishment for @IlhanMN and @RashidaTlaib over their criticisms of Israel. It's stunning how much time US political leaders spend defending a foreign nation even if it means attacking free speech rights of Americans."

Omar added: "It's all about the benjamins, baby" along with some musical note emoji.

That's at once a reference to the Puff Daddy song but more importantly a suggestion that Jewish interests like AIPAC have maintained their power with campaign donations.

Fellow Democrats who are Jewish were not amused.

"At a time when anti-Semitic attacks are on the rise, our leaders should not be invoking hurtful stereotypes and caricatures of Jewish people to dismiss those who support Israel," Rep. Max Rose, D-New York, tweeted.

It's not the first time an Omar tweet has drawn allegations of anti-Semitism. Her arguments against US support for Israel are at this point being overtaken by the tweets. Omar is one of just three Muslims on Capitol Hill and she supports more support for Palestinians and a boycott of Israel.

That Omar should be accused of anti-Semitism after criticism by McCarthy is thick with irony since McCarthy, the top Republican in the House, faced his own controversy last October when he said on Twitter that billionaires like Michael Bloomberg and Tom Steyer -- two men with Jewish heritage -- were trying to "buy" the election the day after a pipe bomb was sent to George Soros' house.

Omar and Trump's tweets are different in that she is making a policy point and he is simply trying to tease Warren and remind people of a controversy following her (the same way he consistently found ways to remind voters about Clinton's email practices in 2016).

But the two sets of tweets are the same in that social media potshots and taunts, regardless of racial insensitivity, feel normal now. Add them to the daily reminders of the racial fissures dividing this country.