According to the poll, 58 percent said they have a favorable view of Clinton, against 39 percent who said unfavorable. It’s the first time since 2008 the former secretary of State’s favorability rating has dipped below the 60 percent mark.

Clinton’s favorability rating is down from 64 percent in April, while her unfavorability rating is up from 31. Her 33 percentage point net positive favorability rating in April has been reduced to 19 points in June, a 14 point drop.

Clinton has seen her support erode most significantly among political independents, going from 63 percent favorable in April to 52 percent in June.

It’s the second consecutive poll to show Clinton’s favorability rating in decline, and an indication that the months-long investigation into the terrorist attacks in Benghazi, Libya, have taken a toll on the reputation of the former secretary of State.

According to a Quinnipiac University poll released in late May, 52 percent said they have a favorable view of Clinton, against 40 unfavorable. That’s down from her all-time high of 61 percent favorable and 34 percent unfavorable in the same poll from February of this year.

House Oversight Committee Chairman Darrell Issa (R-Calif.) last month subpoenaed State Department documents related to the Obama administration’s talking points about the attack. The State Department has released more than 100 emails related to the talking points, but Issa has called the release “incomplete.” Some lawmakers have said they want Clinton to return to the panel to provide additional testimony.

Many Republicans say the Obama administration, through the State Department, misled the American people about the nature of the attacks in the days following the siege that killed Ambassador Chris Stevens and three other Americans. 

White House officials have said the talking points were constructed at a time when it was too early to draw concrete conclusions about the nature of the attacks.

Still, Clinton is one of the most popular public officials in the country and remains the frontrunner in the 2016 presidential race.

The Gallup survey of 1,529 adults was conducted between June 1 and June 4 and has a 3 percentage point margin of error.