Most Americans think Karl Rove crossed the line in questioning Hillary Clinton's fitness as a presidential candidate, according to a Washington Post/ABC poll released Wednesday.

The survey found that 66 percent Americans disapproved of "the Republican strategist Karl Rove raising questions about Hillary Clinton's age and health," while just 26 percent approved. The survey didn't ask how many Americans had been aware of Rove's comments, or go into further detail about what they were.

Partisanship factored into the responses -- Democrats were most likely to oppose the comments, with 84 percent finding them unacceptable. But some Republicans and independents who said they wouldn't support a Clinton candidacy still viewed Rove's comments negatively. Republicans, few of whom back Clinton, were about evenly split, with 45 percent approving of Rove's comments, and 46 percent disapproving. Just about half of independents supported Clinton's candidacy, while 64 percent disapproved of Rove's comments toward her.

Rove questioned Clinton's health earlier this month, saying "we need to know" whether she sustained a traumatic brain injury. He later told reporters that he never said she had brain damage but that she would need to be more forthcoming about her medical history. In a more recent interview, conducted after the poll was taken, he said Clinton was at risk of being seen as "old and stale."

As The Washington Post notes, raising questions about an opponent's health is not a new tactic, and many Democrats in 2008 reported being uncomfortable with Sen. John McCain's (R-Ariz.) age. A recent Pew Research poll found that more than a third of Americans thought they'd be less likely to vote for a candidate in their 70s. But the message may be a tougher sell coming from Rove. In 2010, just 14 percent of Americans gave Rove a positive rating, while 31 percent rated him negatively, and 55 percent were neutral or undecided).

HuffPost Pollster, which includes all publicly available polling, puts Clinton's favorability rating at about 50 percent, though that's down from her recent high in popularity as secretary of state.

The Post surveyed 1,017 adults between May 21 and 25, using live phone calls to reach both landlines and cell phones.