Former Secretary of State Hillary Clinton's fumbles and bumbles in the rollout of her latest memoir, Hard Choices, has knocked the wind out if her easy sail to the White House and put her support in key 2016 presidential election matchups below 50 percent for the first time.

At a time when she should be padding her lead over the top Republican contenders, her underwhelming effort has cut her numbers, said pollster John Zogby.

In his latest Zogby Analytics survey taken June 27-29, for example, her commanding leads over former Florida Gov. Jeb Bush, Kentucky Sen. Rand Paul and New Jersey Gov. Chris Christie have shrunk greatly, and she doesn't even receive 50 percent of the vote. Worse, her support among married and wealthy voters has plummeted.

Zogby told Secrets, “Even more than her dwindling leads over GOP contenders is that while she is pretty much running against herself, in a very high-profile book tour, she is losing ground. Her biggest problem, I have always felt, is the inevitability factor. It help do her in in 2007-2008 and right now looks to be her major nemesis. She has this whole playing field to herself and is declining in the polls.”

He called her book tour performance “lackluster,” one that has been plagued with missteps like when she described herself and her husband as "dead broke" upon leaving the White House. The comment drew attention to the tens of millions of dollars they have collected since leaving the White House.

Zogby also warned that since virtually every voter knows — and has an opinion of — Clinton, there isn’t much she can do to broaden her support.

“It is significant that in every case the runaway favorite again polls under 50 percent and that both Governor Bush and Senator Paul continue to increase their support among key groups. Clinton has almost universal name recognition among likely voters and it is unlikely that she could say or do anything to increase her support base,” said Zogby, who provides Secrets with his weekly report card on President Obama, published Saturday mornings.

In the matchups, Clinton now leads Bush, 47 percent to 35 percent. She once held an a 18-point advantage. Against Paul, she leads 48 percent to 36 percent, but once had a 21-point lead. And she would beat Christie 48 percent to 33 percent, but once led, 52 percent to 29 percent.

Paul Bedard, the Washington Examiner's "Washington Secrets" columnist, can be contacted at pbedard@washingtonexaminer.com.