The CPC gathering at Baltimore's Inner Harbor is an annual event designed to rally Congress's most liberal bloc behind a strategy for pushing its policy agenda. But after November's elections put Republicans in charge of the White House and both chambers of Congress, liberals see themselves as the last line of defense against the GOP's promised attacks on President Obama's legislative achievements.

"In a year when many progressive issues hang in the balance, this will be a vital opportunity for progressive leaders on and off the Hill to come together, build power collectively, and strengthen the resistance against hatred, bigotry and discriminatory policies," reads an introduction to the retreat.

"American values of liberty and inclusivity are under threat."

ADVERTISEMENT

Warren, an icon of the left whose star rose largely because of her tough positions on Wall Street, is scheduled to address the retreat on Saturday morning.

She hasn't said what topics she'll broach, but the event arrives just a day after Trump signed an executive order rolling back parts of the Dodd-Frank financial reform law, which established many consumer protections championed by Warren.

Other speakers slated to address the CPC conference include House Minority Leader Nancy Pelosi (D-Calif.); Rep. Raúl Grijalva (D-Ariz.), a co-chairman of the CPC; Angelo Carusone, president of Media Matters; Jeremy Ben-Ami, executive director of liberal Jewish group J Street; and Jeffrey Sachs, economics professor and director of the Center for Sustainable Development at Columbia University.

The retreat arrives as one of the leaders of the Progressive Caucus, Rep. Keith Ellison (D-Minn.), is in the midst of a fierce contest to take the helm of the Democratic National Committee (DNC).