@layman,
Precisely.
He could have said "I think it was/wan't obstruction of justice."
He's no longer the FBI Director he can say whatever he believes, but he chose to imply that it was, in part by not answering the direct question.
I've been fired. It sucks, even when you know it was for political reasons, so with this and Trump's stupid tweets and "nut job" comment (assuming that actually happened) I can certainly understand why he loathes the president, but this is a guy who had a long term reputation for integrity. During his testimony he refrained from jumping on the leading questions of Dem Senators but he skillfully painted the picture he wanted to paint and which he knew the MSM would eat up...despite the fact that it is all based on hearsay.
The bit about Trump being a liar was to create a counter-point for him:
"We all know he's a liar so that must mean I'm telling the truth!"