Zoe Lofgren is the only member of Congress to take part in all 3 modern day impeachments

Impeachment investigations have only taken place four times in U.S. history -- three in modern times -- and Rep. Zoe Lofgren, who is serving as one of seven House impeachment managers during the trial of President Donald Trump, is witnessing this rare and historic process firsthand for the third time.

The 72-year-old Democratic congresswoman, who has been representing California in Congress since 1994, was a staffer to Rep. Don Edwards while he served on the House Judiciary Committee during the 1974 impeachment of President Richard Nixon.

And during the impeachment trial of President Bill Clinton in 1999, Lofgren was a member of the House Judiciary Committee.

After getting appointed by House Speaker Nancy Pelosi to serve as an impeachment manager during Trump's Senate trial, Lofgren reflected on her roles over the years in a series of tweets.

"As the only member of Congress who has participated as part of the Judiciary Committees for all three modern impeachment proceedings, I must be clear that this is not something I sought or relish," she wrote. "Impeachment is a grave & solemn matter. It's a stress test for our democracy. I hope every Senator is prepared to seriously consider & vote honestly with an open mind for the future of our democracy."

After voting to impeach Trump in December, Lofgren wrote a Newsweek op-ed titled, "This is the third impeachment I've worked on. It's by far the most serious," and reflected on her decision to vote against the impeachment of Clinton at the time.

"In the case of President Bill Clinton in 1998, there was no foreign interference, no election meddling and no attempt to subvert our Constitution. I was a member of the Judiciary Committee at the time of the Clinton proceedings, and it was clear to me that the president's marital dishonesty would not destroy our constitutional form of government," Lofgren wrote.

And during a December appearance on ABC News' "This Week," Lofgren told ABC News Chief Anchor George Stephanopoulos that Nixon "abused his power" to improperly influence the election, but that Trump not only "abused his power;" he "used a foreign power to do it."

The congresswoman, who helped present opening arguments at the Senate impeachment trial on Wednesday, joins House Intelligence Committee Chairman Adam Schiff, Judiciary Committee Chairman Jerry Nadler and Reps. Hakeem Jeffries, Val Demings, Sylvia Garcia and Jason Crow in presenting the Democrats' case against the president.