GOP strategist Karl Rove last week suggested not once, not twice, but repeatedly that Hillary Clinton had suffered traumatic brain damage in a 2012 fall.

“Thirty days in the hospital? And when she reappears, she’s wearing glasses that are only for people who have traumatic brain injury? We need to know what’s up with that,” Rove was quoted as saying in last week’s remarks.

In reality, Clinton spent three days, not 30 days, in the hospital. And in her subsequent appearance before Congress on the Benghazi tragedy, she proved herself deft as ever in rebutting GOP attacks.

“Karl Rove has deceived the country for years, but there are no words for this level of lying,” a Clinton spokesman said in response to his comments. “She is 100 percent. Period.”

Later, Rove denied using the actual term “brain damage,” but then went on to essentially double down on his remarks. So what’s he up to?

Over the past six years, we’ve seen an amazing level of anger and spite leveled at Barack Obama, usually accompanied by pious conservative regret that in Obama, we have been saddled with “the most divisive president ever.” For Republicans, the claim has served as a way to duck personal responsibility. “It’s not our fault we act like this,” they’re saying. “Obama made us do it.”

But Obama did not make them do it. On the contrary, history shows any Democratic president would be “the most divisive ever” in the eyes of Republicans, and would inspire at least as much vitriol, if not more.

Think back to the 1990s and how whack-a-doodle many Republicans became about both Bill and Hillary Clinton. Back then, the president was a drug-smuggling rapist, the Clintons murdered their aide Vince Foster, and Hillary was a man-hating lesbian femi-Nazi. Now that same pattern has repeated itself with Obama.

And while race has played a complicating role in the reaction to Obama, it’s easy to overestimate its impact. Yes, a portion of the GOP base is deeply unsettled by the demographic change occurring in the country; and yes, Obama’s face, name and biography make it easy to play to that anxiety. But the ridiculous string of allegations against him, from the “whitey tape” to the birth certificate to Benghazi and Fast & Furious, are the same brand of allegations flung at Clinton. They’ve simply been adjusted a bit to take advantage of Obama’s background.

Now it’s Hillary’s turn. Her case is interesting because not too long ago, she had been cast in the quite different role as the Republicans’ favorite Democrat. “If only the Democrats had elected Hillary instead of Obama, we wouldn’t be like this,” the suggestion seemed to be. She was depicted as moderate, reasonable, experienced — everything Obama supposedly wasn’t. She was someone the Republicans could have respected and worked with, if only the Democrats had chosen more wisely.

These days, not so much. The Benghazi hearings are in essence the Whitewater hearings, resuming after a 20-year hiatus. The anti-Hillary vitriol on talk radio is back. And Rove is signaling once again that nothing is off the table, and no claim is too ridiculous or vicious. It’s a message to fellow conservatives, and it’s a warning to Hillary herself that things are going to get ugly.