Historians will prepare first drafts in the weeks ahead, assessments of Speaker Nancy Pelosi’s (D-Calif.) two four-year runs guiding the House. It’s a good moment to reflect upon the legacy of a leader who is a hero to millions, yet vilified by opponents.

A nonpartisan summary of any sound first draft will note three things: Pelosi is the most powerful woman in American history. She is the most consequential legislator of the post-Watergate era. She is the most successful and enduring messenger for the modern Democratic party.

Pelosi’s legacy confirms that there are two basic types of political leaders. The first seeks power as a means to an end, a tool with which to improve citizens’ lives. Think of Reagan, Obama, or Gingrich. Each sought power to change policy.

The second type of leader seeks power as an end in itself. They will exploit national divisions and ride any set of issues that works with 51 percent of voters. Power offers them an affirmation of the reverence to which they feel entitled. Both major political parties have some folks like this. Voters trust their gut to identify and avoid them.

The history of Nancy Pelosi’s two four-year speakerships — divided by eight years of the challenging speakerships of John Boehner and Paul Ryan — will confirm she is in the former group.

One thing historians will not have to search for is a verbatim account of who said what to whom. In some Washington meetings, an insider cautions: “nobody takes notes.” Confidentiality helps in negotiating political deals. For the first Pelosi speakership, the public now has virtual transcripts revealing how things work deep inside the sausage-making factory where laws are made.

Republicans and Democrats who worked on the Hill between 1975 and 2013 thought of John Lawrence as a rock-solid staffer, loyal to his leader and spare with his personal agenda. For decades he served as chief of staff to Pelosi, and previously to Natural Resources Committee Chairman George Miller, the burly Californian who came to serve as Nancy Pelosi’s consigliere.