(CNN) Jeff Sessions' memory isn't exactly stellar. Particularly when it comes to what he knew about interactions between President Donald Trump's campaign and Russia.

That's a problem -- especially when you are the nation's top law enforcement official.

Here are threeoccasions -- collected by the one and only Marshall Cohe n -- in which Sessions either forgot or misremembered important details about contacts between Russia and Trumpworld.

1. January 10, 2017

In his confirmation hearing in front of the Senate Judiciary Committee, Sessions is asked this by Minnesota's Al Franken: "If there is any evidence that anyone affiliated with the Trump campaign communicated with the Russian government in the course of this campaign, what will you do?"

Sessions responds: "I'm not aware of any of those activities. I have been called a surrogate at a time or two in that campaign and I did not have communications with the Russians, and I'm unable to comment on it."

2. January 17, 2017

In response to a written questionnaire Sessions submitted as part of the confirmation process, he responded "no" to this question from Vermont Sen. Patrick Leahy (D): "Have you been in contact with anyone connected to any part of the Russian government about the 2016 election, either before or after election day?"

Why this is wrong : We know that on at least two occasions Sessions met with then-Russian ambassador Sergey Kislyak during the campaign. The first came on July 20, 2016 at the Republican National Convention in Cleveland -- when the two men (plus Carter Page!) met at a diplomacy and foreign affairs event. Then on September 8, 2016, Sessions met with Kislyak in his Senate office. Sessions said that meeting was in his formal capacity as a senator as opposed to his role as a Trump surrogate and, therefore, he didn't perjure himself. (Side note: On his forms applying for a security clearance in November 2016, Sessions also did not disclose any interactions with Kislyak.)

3. October 18, 2017

Sessions again testifies before the Senate Judiciary Committee. Franken, again, asks him a tough question: "You don't believe that surrogates from the Trump campaign had communications with the Russians? Is that what you're saying?"

Sessions responds: "I did not and I'm not aware of anyone else that did, and I don't believe it happened."

Why this is wrong : Page says he told Sessions that he was going to Russia in July 2016. And Sessions intervened when Papadopoulos bragged that he could set up a meeting with Russian officials as far back as the end of March 2016.

The Sessions defense goes something like this: He forgot about his meetings with Kislyak because they were either brief or not related to his role as a surrogate for the Trump campaign. Page told him he was going to Russia in an unofficial capacity. And so on and so forth. (Side note: I can't figure out a smart Sessions defense of the Papadopoulos meeting and suggestion of a Russia trip.)

The point is that if you look at all of these things in just the right light, Sessions is being totally honest and transparent -- in both his public and private statements.

But, if you don't see them in just that light, there's a WHOLE lot of smoke swirling around the attorney general right now. "I forgot" might work once. Maybe even twice. Three times? Eh, no.

Think of it this way. Your sixth grader forgets his homework at school one time. Chances are, you are willing to chalk it up to being an honest mistake. When he forgets his homework the second time, you are less convinced it's just by chance. When he forgets it the third time, you are totally sure that he is forgetting his homework on purpose.'

This is at least Sessions' third time forgetting his homework. And the likes of Franken aren't going to simply accept the "whoops" excuse.