According to a new Marist Poll, Hillary Clinton's big lead over her Republican rivals in 2016 is fading.

McClatchy:

Potential Democratic presidential candidate Hillary Clinton’s lead over a crowded prospective Republican field has narrowed and her support has slipped below 50 percent, according to a new McClatchy-Marist poll.

Clinton remains ahead of potential Republican rivals including Gov. Chris Christie of New Jersey, former Gov. Jeb Bush of Florida and Sen. Rand Paul of Kentucky. But recent gaffes by the former secretary of state have helped close the gap.

For example, Clinton leads Christie 47 percent to 41 percent with 12 percent of voters undecided. In April, she led 53-42 with 5 percent undecided, and in February she enjoyed a 58-37 lead against the governor with 6 percent undecided.

She’s seen her cushion against Bush, brother of former President George W. Bush, erode to 48 percent to 41 percent with 10 percent undecided. That’s down from 55-39 with 6 percent undecided in April.

And against Paul, her lead has shrunk to 48 percent to 42 percent with 10 percent undecided from 54-40 and 6 percent undecided in April.

Lee Miringoff, the director of the Marist Institute for Public Opinion in New York, which conducted the survey, attributed the slippage to Clinton’s increased visibility in promoting her new book, “Hard Choices,” and some recent gaffes.

Clinton caused a stir in June when she said that she and former President Bill Clinton left the White House in 2001 “dead broke” and in debt, a statement many potential voters found hard to accept given that both Clintons received millions of dollars in book deal advances and commanded six figures on the speech circuit.

I think more than any gaffe, recent foreign crisis have highlighted what may be her Achilles heel; her performance as secretary of state. The Russian "reset," the failure to reach an agreement with the Iraqis to keep some American troops in the country, and the general state of angst in the world about American leadership - or lack thereof - have combined to get some voters to reassess their opinion of her abilities.

It's still early and voters are not focusing on the race, so the poll is mostly useless except as a snapshot of opinion in late summer, 2014.It shows that the Republicans have a lot of work to do if they are going to beat whoever emerges as the Democratic nominee.