WASHINGTON (MarketWatch) — Bill and Hillary Clinton’s rapid accumulation of wealth after leaving the White House has always been a bit baffling, but it took a presidential campaign and a provocative new book to put a label to it.

That name is corruption. And it is a word Peter Schweizer does not hesitate to use in “Clinton Cash,” even while acknowledging that “proving corruption by a political figure is extremely difficult.”

But the phenomenon of the Clintons’ wealth — their net worth is estimated at well in excess of $100 million — is hard to explain any other way.

“No one has even come close in recent years to enriching themselves on the scale of the Clintons while they or their spouse continued to serve in public office,” Schweizer writes. “The ability of any other ex-politician, whether a former president, senator or congressman, Republican or Democrat, to accumulate such large amounts of money in such a short period is unmatched. It’s not even close.”

“ But even supporters say that for all her good qualities, the former secretary of state seems to be her own worst enemy in creating ethically compromised situations, or at least the appearance of them. ”

Predictably, the vast network of Clinton supporters has pulled out all the stops, not so much to address the individual cases researched by Schweizer and the pattern of behavior they suggest, but to dismiss his book as a political hatchet job and to discredit the writer. This was done even before the book was actually released.

After the book came out on Tuesday, the Clinton campaign launched a barrage of defensive actions starting with a YouTube video mostly containing assertions by spokesman Brian Fallon that the book’s claims are “dead wrong.”

A separate report by the campaign offers a rebuttal of some of the details contained in the book, though a good deal of the supportive material consists of undocumented assertions by Clinton apologists, including the Daily Beast’s Michael Tomasky.

Hillary Clinton, whose efforts to outline the agenda for her presidential campaign have been overshadowed by the controversy over the book, has not directly responded to its accusations.

The New York Times, well known for its liberal editorial stance, has nonetheless called on the candidate to be more forthcoming about the foreign donations to the Clinton Foundation, many of them in apparent violation of a pledge she made that none would be accepted in the four years she served as secretary of state.

“She needs to do a lot more,” the Times editorial board said, “because this problem is not going away.”

The Times, the Washington Post and other media outlets have taken the unusual step of using Schweizer’s research as a springboard for their own reporting on potential conflicts of interest and ethical violations in the foundation’s business and the couple’s speaking activities.

So when they say it’s not going away, you can be sure it’s not going away.

Instead, Bill Clinton has stepped up to defend the foundation and to deny any improprieties — sort of.

When the former president, who defended himself against impeachment charges of perjury by parsing what the meaning of “is” is, qualifies his defense of the foundation’s practices by saying the couple never did anything “knowingly inappropriate,” it is bound to raise eyebrows.

When he went on to say in an interview this week with NBC that he will continue to make speeches at hundreds of thousands of dollars a pop even while his wife is running for president, he invited ridicule by explaining, “I gotta pay the bills.”

Not only is this rank hypocrisy given his net worth, but remarkably disdainful to people who will not earn in decades what he collects for an hour-long speech, as they scrape by in low-paying jobs because they really do have to work to pay the bills.

It is the speaking fees — ranging as high as $500,000 to $750,000 for a single speech — that are the most obvious payments pointing to corruption, although the murky operations of the foundation and its non-charitable expenditures also raise many questions.

The former president likes to smile and chuckle that he’s just happy people still want to listen to him, even though he’s smart enough to know that no one pays half a million dollars just to hear his ruminations on world affairs 14 years after he left office.

His impolitic remarks in the NBC interview were delicately described by the Washington Post as indicating the former president might be “out of touch,” whereas it will strike many as yet another moral blind spot for a politician whose enduring charm and charisma continue to make him popular.

Hillary Clinton’s campaign spokesmen have said there is not a “shred of evidence” to support claims that the speaking fees or foundation donations involved any quid pro quo, a defense, which, after Clinton acknowledged destroying whatever emails on her private server she chose, has an irony of its own.

But even supporters say that for all her good qualities, the former secretary of state seems to be her own worst enemy in creating ethically compromised situations, or at least the appearance of them.

A Wall Street Journal/NBC poll out this week found that only 25% of those surveyed consider the presidential candidate honest and straightforward, down from a none-too-resounding 38% last summer.

The question is rapidly becoming not whether Hillary Clinton’s good qualities and her unique skill set outweigh her bad qualities to make her an acceptable candidate for the White House, but whether her bad qualities should disqualify her from holding public office.

There is a whiff of desperation in the defenses being mounted by the campaign and Clinton supporters. The portrayal of Clintons as victims is wearing a little thin.

Democrats have not yet abandoned ship, but reports are surfacing that New York Mayor Bill de Blasio is secretly preparing to challenge Clinton for the nomination, and other potential candidates may be making quiet plans of their own in case Clinton’s campaign implodes.