Washington (CNN) -- How much do Republicans fear Hillary Clinton as the likely Democratic presidential nominee in 2016? So much that Karl Rove has her in his sights.
The conservative political mastermind credited with orchestrating George W. Bush's two winning presidential campaigns insinuated in a fact-challenged attack last week that Clinton was brain damaged.
Condemnation from Democrats and some Republicans came quickly, but Rove achieved his goal of inserting the question of Clinton's health into the national discussion before she has declared if she will run in an election more than two years away.
On Wednesday, Former President Bill Clinton came to his wife's defense, joking during a public appearance that if Hillary had brain damage, "then I must be in really tough shape because she's still quicker than I am."
"It's just the beginning"
"It's just the beginning," he said of Rove's attack, adding that Republicans "will still get better at it."
When it comes to playing a political card, few deal better than Rove, who specializes in undermining the perceived strengths of opposing candidates.
Recall the 2004 "swift-boating" of John Kerry, who saw one of his biggest potential advantages -- his military service in Vietnam compared to Bush's non-participation -- turned into a liability by questions about what he did there.
Now Rove takes on a former U.S. senator and secretary of state who is the overwhelming favorite for the Democratic nomination, if she decides to run. Clinton also polls strongly against all the known potential Republican contenders, a situation that likely prompted Rove to go after her.
In comments at a May 8 conference reported by the New York Post's Page Six gossip column, Rove said Clinton spent 30 days in the hospital in 2012 and wore "glasses that are only for people who have traumatic brain injury" when she returned to public life.
Both assertions were false -- she spent a few days in the hospital and the glasses help deal with double vision rather than traumatic brain damage.
Nevertheless, the comments generated headlines and political chatter, including repeated discussions on CNN programs.
Nick Merrill, a spokesman for Clinton, said Rove lied about Clinton's health but "he doesn't care, because all he wants to do is inject the issue into the echo chamber, and he's succeeding."
"It's flagrant and thinly veiled," Merrill said, adding that Republicans "are scared of what she has achieved and what she has to offer."
As for Clinton, he said "she is 100%, period."
Even former House Speaker Newt Gingrich, a GOP political adversary of the Clintons in the 1990s, blasted Rove's comments as typical of what he called a Republican consulting class that "wants to be negative, narrow, personal, avoid ideas and not have to wrestle with the big issue."
Rove's tactic not only drew attention, it linked the controversy he started to the dominant Republican attack line against Clinton so far -- her management of the September 11, 2012, attack on a U.S. diplomatic compound in Benghazi, Libya, that killed Ambassador Christopher Stevens and three other Americans.
House Republicans have formed a select committee on Benghazi, a step intended to keep the issue in the public eye, while Democrats oppose the move and have yet to decide if they will take part.
Two months after the Benghazi terror attack, Clinton suffered a blood clot following a fall. She underwent testing in a hospital, then later was admitted for a three-day stay.
The health issue prevented her from testifying to Congress about the attack, and some Republicans questioned the validity of her health problem at the time.
Rove brought up all that history on Tuesday when he backed away from his factual errors but stressed the overall issue of Clinton's health.
"I didn't say she had brain damage. She had a serious health episode," Rove told Fox News before reciting a chronology of what happened in December 2012 and January 2013.
"First she had apparently a serious virus," he said. "They announced then on the 15th of December that she had at some period in the past week fallen. They didn't say when, they didn't say where. She was recovering at home."
Later in December, Rove continued, "she goes in and turns out to have had a blood clot" but "they won't say where."
"The next day, they say it is between her skull and her brain behind her right ear," he noted. When she testified before Congress on Benghazi on January 25, Clinton wore "special glasses that allow her to deal with the double vision that this episode caused," Rove added.
In response, Bill Clinton ridiculed Republican efforts to politicize the entire Benghazi issue.
"First they say she faked her concussion," he noted Wednesday, and now they have her "auditioning for a part on the Walking Dead."
If elected in 2016, Clinton would be 69 when she becomes president -- the same age as Ronald Reagan when he moved into the White House in January 1981.
Age a campaign issue?
Republican commentators repeatedly made that point Wednesday, saying Democrats defending Clinton had questioned the age of Republicans such as Reagan, Vice President Dick Cheney and Sen. John McCain when they ran for higher office.
GOP strategist Kevin Madden called Rove's "erroneous" remarks an acknowledgment of reality rather than a strategic ploy.
"I think it was a very awkward attempt at making a pretty obvious point, which is that non-candidates, which Hillary Clinton technically is, they don't get a level of scrutiny that official candidates in a 2016 race might get," said Madden, a CNN contributor.
Shenanigans, responded Democrats.
"It's the McCarthyism of the Internet age where you can put anything out there, make a big lie, make this thing up about 30 days in the hospital, which was patently not true, make this thing up about sunglasses," said Richard Socarides, a former adviser to Bill Clinton. "It was totally fabricated. Then he pulls it back. Now we're having this whole segment on it."
Tracy Sefl, a senior adviser for Ready for Hillary, one of the super PACs formed to back a Clinton candidacy, said Rove's tactic would backfire on Republicans because it boosted support for Clinton.
Madden responded that vilifying Rove amounted to a Democratic counter-strategy.
"The reason that we're talking about this today has less to do with whether or not some of the facts related to Hillary Clinton's health," he said. "It has to do with the fact that now while Hillary Clinton is not an official candidate, her organization and her supporters, they're acting like one. They seized on this as an opportunity to drive a contrast with someone like Karl Rove, to express some outrage and maybe engender some sympathy for Hillary Clinton."
CNN's Paul Steinhauser contributed to this report.