If you’re Hillary Clinton, the answer to the above question is: Very.

In Democrats’ sixth debate Thursday, she pointedly accused Sanders of getting personal in criticizing their party’s leader in the White House.

“The kind of criticism that we’ve heard from Senator Sanders about our president, I expect from Republicans,” Clinton said in the debate’s waning minutes. “I do not expect from someone running for the Democratic nomination to succeed President Obama.”

Sanders retorted that this was a “low blow,” saying he’s worked with the president for seven years (Obama recently hosted him in a private Oval Office meeting) and that, together, Democrats have “made enormous progress.”

So who’s right? Clinton made a number of charges Thursday when it comes to things Sanders has said about Obama. And as with many things, the true meaning is in the eye of the beholder.

Democratic presidential candidate Hillary Clinton called out rival Sen. Bernie Sanders for his history of criticizing President Obama during the PBS NewsHour debate on Feb. 11. (PBS NewsHour)

But to help you decide, we broke down three notable times Sanders has been less-than-supportive of the president.

1. 2011: “It's not a bad idea” for Obama to have a primary challenger

Let’s start with this:

In the spring and summer of 2011, as Obama was gearing up for reelection, Sanders wondered to the media about how it might be good for someone to challenge Obama to push the president to the left. Obama had moved “far to the right,” Sanders explained, and was making “weak” deals with Republicans.

In fact, Sanders’s quote to WNYC back then basically summarizes his rationale for jumping into the 2016 race:

If a progressive Democrat wants to run, I think it would enliven the debate, raise some issues, and people have a right to do that. I’ve been asked whether I am going to do that. I’m not. I don’t know who is, but in a democracy, it’s not a bad idea to have different voices out there.

In Thursday’s debate, Sanders noted he did not choose to be that voice — and that his opponent, Clinton, did.

“One of us ran against Barack Obama,” he said. “I was not that candidate.”

Still, when Sanders did endorse Obama when the 2012 race turned to the general election, he sounded almost reluctant, telling CNN: “I think Obama is by far the preferable candidate. Is Obama doing everything I want? Absolutely not, and among other things, he has not been as strong as he should standing up to Wall Street.”

2. “Read this book”

Just before the Iowa caucuses, liberal radio host Bill Press released a not-so-subtly titled book, “Buyer’s Remorse: How Obama Let Progressives Down.”

To the dismay of Obama supporters, right there on the front jacket was Sanders’s name. His shortened blurb: “Bill Press makes the case. … Read this book.”

In Thursday’s debate, after prompting from Clinton, Sanders defended his blurb, saying it focused more on the future than the past.

The actual blurb reads: “Bill Press makes the case why, long after taking the oath of office, the next president of the United States must keep rallying the people who elected him or her on behalf of progressive causes. That is the only way real change will happen. Read this book.”

Sanders notes that this is hardly a criticism of Obama — nor is it an endorsement of Press’s book.

And Press himself agreed on Thursday night, after the debate. He had this to say on CNN:

“This is a non-issue that the Clinton campaign can’t seem to let go. He did not write a forward to the book. He did not endorse the book. He wrote a blurb. The blurb says what he says in every speech. ... It’s not a criticism of Barack Obama. My book is [a criticism]; Bernie’s blurb is not. So take it out on me. I ain’t running for president.”

That’s a pretty good defense, but for what it’s worth, Sanders did allow his blurb to appear on a book that was clearly critical of Obama. That isn’t something any blurb author should take lightly.

3. Sanders’s campaign is a “course correction”

There’s one thing we can say for certain about Sanders’s comments of Obama: When talking about the president, Sanders often delivers praise with a “but.”

In an October interview with MSNBC, he said Obama and Vice President Joe Biden “have done a damn good job,” but that America needs “a course correction.”

In another MSNBC interview that aired the same night as Thursday's debate, Sanders suggested Obama has failed in closing “the huge gap” between Americans and Congress.

“But I think what we need, when I talk about a political revolution, is bringing millions and millions of people into the political process, in a way that does not exist right now,” he said.

To hear Sanders tell it, his campaign is nothing short of a “political revolution.” And one of his main criticisms of Obama seems to be that Obama hasn’t quite invested his whole heart in that revolution.

Has Sanders been a big Obama critic? Not necessarily. But he has clearly made that case that Obama hasn’t been the president many liberals longed for.