They were accused of attempting to obstruct justice.

他们被控企图妨碍司法公正。

《牛津词典》

In attempting to obstruct justice, we mean by that obstructing the justice of whom?

CNN: Transcript: House manager Gekas' statement on the law

Put another way, if the president didn't obstruct justice, he also didn't commit perjury when he denied it.

CNN

It is a federal crime to commit perjury and obstruct justice in civil cases, including sexually harassment cases.

CNN: Transcript: Judiciary Committee impeachment hearing