WASHINGTON — When it comes to impeachment, Representative Zoe Lofgren, Democrat of California, is arguably the institutional memory for Congress.

She was a member of the House Judiciary Committee in 1998 when it approved articles of impeachment against President Bill Clinton for lying about an affair with a White House intern. And as a young law student in 1974, she helped the committee draft its Watergate charges against President Richard M. Nixon.

Now — 46 years after the Nixon case — the 72-year-old lawmaker will take a high-profile role in the nation’s third impeachment trial, serving as one of the managers who will prosecute the House’s case against President Trump in the Senate.