President Trump fought with the El Paso-born Democratic deputy, Beto O & Rourke, calling him "fake" and telling him to "shut up" before a visit to Texas following a mass shooting.
On Wednesday, Trump will visit El Paso to meet the first responders and pay tribute to the victims of the massacre that killed 22 people.
His presence is treated with caution by some in the city who believe that Trump's anti-immigration divisive rhetoric has played a role in fueling the white nationalism that inspired the armed man.
A few hours before he would have to land, Trump tweeted that the Democratic presidential contender had a "false name to indicate his Hispanic legacy".
The president said he should "respect the victims and the forces of order – and shut up!"
The full name of Beto O’Rourke is Robert Francis O’Rourke, however he was given the nickname Beto as a child to distinguish him from his grandfather. Beto is a common Spanish nickname for those with names like Roberto or Alberto.
Opponents have long claimed that the nickname was produced to create an authentic image for a district with a large percentage of Spanish speakers.
ORourke had previously said: "My parents called me Beto from day one, and it's alone – it's kind of a nickname for Robert in El Paso. It's simply blocked."
"I really don't think that's what people in Texas want us to focus on. … We can focus on small, petty or mean things or we can be big, bold, brave and confident."
He even tweeted his child's picture with a Beto sweater.
President Trump's message on national unity in response to the mass shootings in El Paso and Dayton was denounced for ignoring his incendiary and anti-immigration rhetoric that reflects the language linked to one of the shooters.
It is a very unusual situation for an American president to immediately try to console a community and a nation while being criticized while contributing to a combustible climate that can generate violence.
White House officials said that Trump's visits to Texas and Ohio on Wednesday, where 31 people were killed and dozens injured, would be similar to those he paid to mourning communities including Parkland, Florida and Las Vegas with the president and the first lady who greet the first rescuers and spend time with families and survivors in mourning.
"What he wants to do is go to these communities and grieve, pray with them, offer condolences," White House spokesman Hogan Gidley said. He said Trump also wants to "have a conversation" about ways to avoid future fatal episodes.
"We can do something awesome, challenging to prevent this from ever happening again if we get together," the spokesman said.
This is a difficult task for a president who thrives in the division and whose aides say he considers discord and discomfort about cultural, economic and demographic changes as the key to his re-election.
At the same time, prominent democrats have blamed Trump more often than invoking national unity the day after the shootings, a measure of the deep polarization in the country.
Trump, who often seems more comfortable on rally stages with deeply partisan crowds, has not excelled in projecting empathy, mixing what may seem to be superficial expressions of pain with embarrassing remarks. While he offered hugs to tornado victims and spent time at the bedside of the shooting victims, he has not yet projected the kind of emotion and vulnerability of his recent predecessors.
Barack Obama visibly shaken as he turned to the nation following the massacre of the Sandy Hook elementary school and joined while giving a 2016 speech on new arms control efforts.
George W. Bush helped reunite the country after the September 11 attacks, especially standing on the smoldering rubble of the World Trade Center, with the arm draped over a fireman's shoulder as he screamed through a megaphone. Bill Clinton helped reassure the nation after the bombing of a federal building in Oklahoma City and the mass school shootings at Columbine High School.
Trump was also able to conjure relaxing words. But then it often falls quickly into tweets and divisive statements – just recently depicting immigrants as "invaders", suggesting that four democratic black women congresses should return to their countries of origin, even if all are citizens, and describing black Baltimore as a majority – infested hell hole.
In the Texas border town of El Paso, some local Democratic residents and politicians claimed that Trump is not welcome and invited him to stay away.
"This president, who helped create the hatred that made Saturday's tragedy possible, shouldn't come to El Paso," Beto O & # 39; Rourke tweeted.
"We don't need more division. We must heal. He has no place here. "
In Dayton, Mayor Nan Whaley said he would meet Trump on Wednesday, but told reporters that he was disappointed by his remarks written in Monday in response to the shootings.
His speech included a complaint of "racism, fanaticism and white supremacy" and a statement that "hatred has no place in America".
But he made no mention of any new efforts to limit sales of certain weapons or the anti-immigration rhetoric found in an online counter published just before the El Paso attack.
The mayor of Dayton Whaley said simply, "Everyone has the power to bring people together and everyone has the power to be a force to separate people – it depends on the president of the United States."
The recent Pew Research Center survey found that 85% of US adults believe that the tone and nature of political debate in the country have become more negative, with a majority saying that Trump has changed things for the worse. And more than three quarters – 78% – say that elected officials who use hot or aggressive language to talk about certain people or groups make violence against those people more likely.
— Associated press writers Elana Schor, Deb Riechmann and Darlene Superville and poll writer AP Emily Swanson contributed to this report.