Democrat Hillary Clinton may already have apologized for characterizing half of rival Donald Trump’s supporters as deplorable, but that didn’t stop Trump from piling on Monday.

Clinton said last week that half of Trump’s supporters fit into a “basket of deplorables” — racist, sexist, xenophobic, homophobic and/or Islamophobic. Trump also has been criticized for his apparent legitimization of the alt-right and remarks about Mexican immigrants and Muslims. She later apologized for saying half but did not back off the concept.

As Clinton rested Monday because of a bout with pneumonia, Trump went on the offensive, calling her “deplorables” remark “an explicit attack on the American voter that makes her unfit for the presidency" during a speech to the National Guard Association conference in Baltimore. Trump alleged Clinton’s remarks were aimed at those in uniform — both military and police.

“You cannot run for president if you have such contempt in your heart for the American voter,” Trump said. “You can't lead this nation if you have such a low opinion of its citizens.” He also said he is the only candidate who can represent all Americans.

Trump’s position is at odds with his own rhetoric. He has attacked a Mexican-American judge handling a lawsuit against Trump University, saying he doubted the judge could be impartial because of his heritage. He also said he didn’t think a Muslim judge could be impartial in a case involving him. Earlier in the campaign he pledged to build a “big, beautiful wall” along the Mexican border to keep people from crossing illegally and has called for a moratorium on immigration by Muslims.

"You know what's deplorable? Hillary Clinton viciously demonizing hard working people like you," a Trump campaign ad scheduled to air in Ohio, Florida, Pennsylvania and North Carolina concludes.

Trump told Fox News early Monday Clinton’s remark was probably the “single biggest mistake of the political season.”

Whole Trump has been mocking Clinton’s stamina for months, he was strangely quiet about her fainting spell Sunday at the 9/11 commemorative ceremony in New York and her current illness, saying only he hopes she gets well soon. The collapse and a coughing fit last week have made Clinton’s health a campaign issue.