Ulasewicz was clearly not one of the major players in Watergate. Yet, the Senate Select Committee investigating the 1972 election under its Chair, Sam Ervin, thought it was essential to hear Ulasewicz. Ulasewicz’ testimony helped to provide what has become the Watergate narrative. No matter how critical and believable John Dean’s testimony may have been, bit players like Ulasewicz helped to provide the framework and credibility needed to persuade voters that Nixon should be impeached.
Unfortunately, the House Democrats seem to be on another path as they try to persuade voters that Trump should be impeached. House Democrats seem to think that the testimony of McGahn and Mueller will overcome both the burden of reading the Mueller Report and the lifelessness that can plague a lengthy written document. Given the clear intent of the Trump Administration to slow-walk the appearance of any critical witnesses, it is rather strange that House Democrats don’t want to hear from some of the lesser witnesses.
https://www.nytimes.com/2019/05/08/us/politics/impeach-trump-democrats.html