That is not entirely accurate.
Sekulow said several times that Trump had NO involvement in the drafting of the statement WHATSOEVER. None. Zero. Zilch.
Sanders then later said he had a little input, some suggestions, "as any father would."
What has happened is that people like Hope Hicks, who openly spoke about deep sixing the emails to and from Donny Jr that prove collusion efforts, has no doubt told Mueller and others that Trump dictated the fricking thing.
Knowing that, the Trump lawyers tried to get out in front of this by sending that letter to Mueller admitting it, but saying its no big deal.
See, this is the problem with lying over and over again, and about big things. You can't get the details straight. And then you get your story mixed up and it starts not to match the facts, or other people's stories.
And in this case, that was because it was part of a concerted effort by Trump and his team, directed personally by Trump, to hide the facts of the meeting.
Lock his orange azz up!!