He writes a weekly column on Senate history for a Washington newspaper and is the co-author (with Neil MacNeil) of The American Senate: An Insider's History, published in 2013, a history of Senate rules and customs.
During the weekly luncheon meetings of the Democratic Caucus of the United States Senate, Baker opened up with a brief  historical anecdote or minute. These short essays were wide-ranging in topic and highlight recurring themes in the Senate's institutional development. This program, at the request of Minority Leader Reid, was discontinued in the 109th Congress, in order to make the meetings more efficient, but Leader Reid ordered it resumed six months later. In 2009, at the time of Baker's retirement, Senate Republican Leader Mitch McConnell initiated a similar program for his party's members. Both Democratic and Republican programs are currently active, relying on presentations by the Senate's Historian and Associate Historian.