WASHINGTON (AP) — As Hillary Rodham Clinton promotes her book, liberals in the Democratic Party are elbowing into the 2016 presidential conversation while pitching populist messages on the economy and immigration.

Potential Clinton rivals like Vice President Joe Biden, Massachusetts Sen. Elizabeth Warren and Maryland Gov. Martin O'Malley are in the middle of a summertime tour of Democratic conferences and campaigns, drawing contrasts to Clinton as she weighs a heavily anticipated second presidential bid.

Biden and Warren are addressing an organization of young Democratic activists, Generation Progress, on Wednesday and speaking at the annual Netroots Nation conference later in the week, putting them before liberals who form a core of the Democratic base. O'Malley has been exploring a presidential campaign and made stops in Iowa and New Hampshire in the past month.

(Story: Ken Thomas, The Associated Press)