THERE are many patriotic Americans who have cheered Donald Trump's path all the way to the Republican presidential nomination who will now surely be feeling shamed of themselves. Trump has mocked the mother of an American soldier killed in Iraq in 2004. The man, US Army Capt Humayun Khan was a Muslim. His father Khizr Khan last week took to the floor at the Democrat Convention to attack Trump's Islamophobia. His wife Ghazala stood beside him as he spoke. In an act of unbelievable insensitivity, Trump later mocked the slain solder's mother for her silence. She later hit back in an an article in the Washington Post calling Trump ignorant about Islam and saying that he did not know the meaning of the word "sacrifice". Most Trump supporters are dumb enough to agree when he attacks Muslims and demands that there should be a ban on them entering the US. But they are not so dumb as to agree that he should deride the family of an American soldier who gave his life for his country. This could surely be a watershed moment for the Trump campaign. His motormouth has finally gone too far. In terms of integration, the US military is arguably the best representation of the whole United States. All ethnic backgrounds are united in the cause of serving their homeland. There is no official discrimination in the ranks. Race is no bar to promotion. The 27-year-old Captain Khan was a professional with a promising military career ahead of him. In the US military, every soldier who is considered good enough to die for his or her country is treated with respect. Individual acts of racism, inevitable in any army, are severely punished. When Trump mocked Captain Khan's mother, he was mocking every American serviceman and woman, those still serving and the veterans who have risked their lives and come home, many of them injured in mind and body. No one has the right to behave so callously, most especially a man who wants to become the commander-in-chief of the armed forces of the United States. Trump has overreached himself with his trade-mark bombast. And over and above his disgusting comments about the Khan family, which have surely alienated many of his good-buddy supporters, his mean-minded comments now clearly demonstrate his total lack of judgment. It is one thing to be an iconoclast who seeks to take on and defeat the corrupt US political establishment — many know such an assault was long overdue — but Trump's methods are now seriously in question. He has also said that he would have liked to punch some of the speakers he heard the the Democrat convention. This is not the behavior of a rational man who understands what is at stake in November's presidential election. Trump may not himself drink, but he shoots off at the mouth like some boorish barroom drunk. One commentator wrote two months ago that Trump was a clever man who knew what stupid people wanted to hear. That assessment must now be seriously in doubt. He is not clever. It is not simply his racism, his blatant Islamophobia that would seem to make Trump totally unsuited to occupy the Oval Office. It is his insensitivity, his sheer lack of judgment that gives the greatest cause for concern.