Rudy Giuliani once captivated Americans with his take-charge leadership after the terrorist attacks of September 11, 2001. He was Time Magazine's man of the year.
That's hard for most under-30 voters to grasp. The former New York City mayor has suffered one embarrassment after another ever since, and has become a staple of comedians' jokes.
This was on display last weekend when, in his role as a leading surrogate for Donald Trump, he went on TV-interview shows to proclaim that the Republican presidential nominee was a "genius" for declaring $916 million in losses that he could use to legally avoid paying 18 years of federal income taxes.
Giuliani also suggested that "everybody" has extramarital affairs, and didn't back down from an earlier assertion that Hillary Clinton was "too stupid" to be president if she didn't immediately believe Monica Lewinsky's account of her White House trysts with President Bill Clinton. The most memorable of Giuliani's encounters was a testy exchange with CNN's aggressive Jake Tapper, who challenged the ex-mayor to defend what he called "unhinged" accusations by Trump about the Clintons' marriage.
This followed a series of Giuliani controversies over the past 15 years. He announced a run for the 2008 Republican presidential nomination and spent much of 2007 leading in the polls. When the campaign actually began, however, he was soundly rejected in New Hampshire and Florida and promptly dropped out.
Earlier, Giuliani's image as a tough defender of law and order had taken took a blow when he pushed President George W. Bush to tap Bernard Kerik as Homeland Security secretary. Kerik had been Giuliani's bodyguard and New York City police chief and then a partner in his security business.
The problem was that he was a crook who was eventually convicted of eight federal felonies, including hiding income from the IRS and lying to the White House about work done by a mob-linked contractor. He spent three years in the slammer before taking up the cause of criminal-justice reform.
Giuliani created a stir last year when he said he does not believe that President Barack Obama "loves America," telling an audience of conservatives that Obama wasn't "brought up the way you were and I was brought up through love of country".
The former mayor has a history of inciting racial controversies; he added to that this year in attacking the Black Lives Matter movement and lecturing black people about pop music and culture.
His recent attacks on Hillary Clinton for her role in defending her husband from women who said they had extramarital affairs with him are full of irony. Giuliani has been married three times. His second wife found out that he was divorcing her by watching him on a television interview. He was having an affair at the time with the woman who became his third wife. When queried about hypocrisy, he said "everybody" is unfaithful.
Nevertheless, Giuliani is a Trump confidant and loyalist. In those weekend interviews he argued that Trump won the debate against Clinton last week though polls and many Republicans indicated otherwise.
If Trump becomes president, Giuliani is prominently mentioned as a possible attorney general - he was US attorney in New York in the 1980s - or Homeland Security chief or even director of the Central Intelligence Agency.
Any of those appointments would produce interesting Senate confirmation hearings.