Most voters aren't paying much attention to Republicans' ongoing investigation into the Benghazi attacks that happened during Hillary Rodham Clinton's tenure as secretary of state. It's a political witch hunt, Democrats cry.

But more than any other problem she's faced so far, the 2012 attack on U.S. diplomatic compounds in Libya that killed four Americans, including ambassador J. Chris Stevens, is seen as fair game for 2016.

In a Washington Post/ABC News poll released Tuesday, 55 percent say how she handled Benghazi is a legitimate issue for the 2016 campaign. Most interestingly, it's far from a partisan issue; that number includes 51 percent of Democrats and half of independents.

The Benghazi attack ranks slightly higher as a legitimate issue for voters than other, more recent negative headlines for Clinton: The Clinton Foundation's fundraising from foreign governments (53 percent) and her use of personal e-mail while she was head of the State Department (48 percent). Both those numbers break down along much more partisan lines, too.

Of course, the fact that voters think Benghazi is a legitimate issue doesn't mean they think it's a negative one for Clinton.

In total, half of voters disapprove of the way Clinton handled questions about the deadly attack, with 33 percent approving. But that breaks down much more along partisan lines; 82 percent of Republicans compared to 23 percent of Democrats disapprove of her response to the questions. So many/most Democrats who see it as a legitimate issue don't necessarily see it as a negative.

This would seem to be good news for Republicans, who have been hammering away at Clinton on Benghazi for three years now, accusing her of getting a free pass and skirting tough questions. In Congress, House Republican lawmakers are on their eighth sanctioned investigation into the incident, with their findings expected to be released in the throes of the presidential election in 2016.

On the presidential trail, GOP candidates have mostly stayed away from the touchy subject, preferring to attack Clinton on other issues, including the money she took for very well-paid speeches since departing as secretary of state (among other problems for the Hillary camp).

Attacking Democrats on Benghazi can be tricky, though. The GOP's 2012 nominee, Mitt Romney, faltered in a debate against Obama on the question.

But Clinton isn't the only presidential hopeful with a complicated issue in the Middle East. The Washington Post/ABC poll also asked voters whether Jeb Bush's hypothetical handling of his brother's Iraq war was a legitimate issue. The former Florida governor's stumbles over the question have produced arguably his most negative headlines thus far.

But the issue seems to be less of an issue for Bush than Benghazi is for Clinton. More voters (48 percent) say no, what he would have done in Iraq is not an issue, while 44 percent say it should be part of the 2016 debate. Again, things aren't as partisan as you might expect -- 44 percent of Republicans say it's a legitimate issue, for example -- but overall, people don't seem as interested in hypotheticals about what George W. Bush's brother would have done if he had been in Dubya's shoes (and with more information).

But perhaps that's because it is precisely a hypothetical question. In the same poll, just 23 percent of Republicans said they think Bush would continue the same policies as his brother if elected.

No one can say for certain whether either Benghazi or the Iraq war -- which recently matched its lowest approval rating in ever among the American public -- will sway voters next November. But these latest numbers should serve as a reminder to candidates that the past is never really in the past.

UPDATE: This post has been updated to reflect that 50 percent of voters disapprove of the way Clinton handled questions about the Benghazi attack.