Although Republican presidential candidate Donald Trump won an impressive landslide victory in the New Hampshire primary on Tuesday, his critics, far from being impressed, have all the more become wary of what the future holds in store for America in case he eventually wins the White House this November.

For instance, Ezra Klein, one of America's progressive columnists, called Trump as "the most dangerous major candidate for president in memory" who "pairs terrible ideas with an alarming temperament."

Writing for the Vox on the day Trump won his first electoral victory, Klein described the Republican bet as a "racist, a sexist, a demagogue ... a narcissist, a bully, and a dilettante."

Klein said Trump "lies so constantly and so fluently that it's hard to know if he even realises he's lying," adding that "he delights in schoolyard taunts and luxuriates in backlash."

As to other critics who call Trump a "joke" or a "clown," Klein said the GOP bet is neither of the two. "He's a man who could soon be making decisions of war and peace, who would decide which regulations are enforced and which are lifted, who would be responsible for nominating Supreme Court Justices and representing America in the community of nations," he wrote.

To better understand Trump's personality, Klein traced the candidate's rise to power: "His business is licensing out his own name as a symbol of opulence. He has endured bankruptcies and scandal by bragging his way out of them ... He climbed to the top of the polls in this election by calling Mexicans rapists and killers. He defended a poor debate performance by accusing Megyn Kelly of being on her period. He responded to rival Ted Cruz's surge by calling for a travel ban on Muslims. When two of his supporters attacked a homeless man and said they did it because 'Donald Trump was right, all these illegals need to be deported,' he brushed off complaints that he's inspiring violence by saying his supporters are 'very passionate.'"

Klein said it's instinctive for Klein to harness people's anger, resentment and fear as his formula for success. To Trump, for Americans to win, others must lose. "We're going to make America great again," he said in his New Hampshire victory speech, "but we're going to do it the old fashioned way. We're going to beat China, Japan, beat Mexico at trade. We're going to beat all of these countries that are taking so much of our money away from us on a daily basis. It's not going to happen anymore."

For all of Trump's negative attributes, the biggest of them is the one that gets less attention. Klein said this is the presidential wannabe's complete lack of shame. "Most people feel shame when they're exposed as liars, when they're seen as uninformed, when their behavior is thought cruel, when respected figures in their party condemn their actions, when experts dismiss their proposals, when they are mocked and booed and protested," Klein noted.

But Trump has apparently no such feeling, Klein said. "He has the reality television star's ability to operate entirely without shame, and that permits him to operate entirely without restraint. It is the single scariest facet of his personality. It is the one that allows him to go where others won't, to say what others can't, to do what others wouldn't," he said.

In short, Klein said, "there is something scary in Donald Trump. We should fear his rise."