What happened Tuesday was the second part of the Trump strategy. The first part was to cooperate with law enforcement. The second part was to not cooperate with congressional impeachment efforts.
Trump has refused to allow White House aides and former aides to testify before the impeachment panel; at the direction of the White House, two former aides, Rick Dearborn and Rob Porter, refused to appear alongside Lewandowski Tuesday. McGahn, also at the direction of the White House, has refused to testify before the committee. The House has gone to court to compel McGahn’s testimony, but a favorable decision is not guaranteed, and in any event will take a long time.
Lewandowski, who never worked in the White House, did appear and made clear he would address the specific contents of the Mueller report. Indeed, when he was asked to confirm this or that passage in the report, he did. In that sense, his testimony was like that of Mueller himself, who sought to stay within the boundaries of the report when he testified before Congress.