Thirteen women Democratic senators endorsed Hillary Clinton at a Capitol Hill fundraising event, the Washington Post reports.

“But one particularly influential female Democratic senator didn’t join her colleagues: Sen. Elizabeth Warren (D-MA) — the anti-Wall Street crusader who was courted to run as the darling of very liberal Democrats — has not endorsed Clinton, nor has she promised she will.”

“Her absence served as an awkward reminder of Clinton’s enduring struggle to generate support and enthusiasm among an influential segment of her party’s most liberal members. It also illustrates the leverage that Warren holds in an election that Democrats are calculating will be waged on issues of economic advancement and fairness.”

Ryan Lizza has a must-read piece on Sen. Elizabeth Warren (D-MA) and what she’s really trying to do in 2016.

“Warren is not running for President. But she is mounting a campaign to insure that Clinton and other prominent Democrats adhere to her agenda of reversing income inequality and beating back the influence of corporate power in politics. These are issues that Warren has pursued for three decades, as an academic, a policy adviser to Democrats, an Obama Administration regulator, and, since 2012, a U.S. senator and the anchor of a progressive wing of the Democratic Party.”

“Clinton has taken notice. Last December, she invited Warren to a private meeting at her Washington home, near Embassy Row, to hear Warren’s advice on issues such as income inequality. In recent months, members of Clinton’s policy team have consulted with Dan Geldon, one of Warren’s closest advisers, about economic policy… Clinton even sounds like Warren these days, evidently hoping to fend off charges that she is a captive of Wall Street money and influence.”

Huffington Post: Warren is still Clinton’s biggest threat even if she isn’t running

New York Times: “For anyone who wondered what kind of economic message Mrs. Clinton would deliver in her campaign, the first few days made it clear: She is embracing the ideas trumpeted by Ms. Warren and the populist movement — that the wealthy have been benefiting disproportionately from the economy, while the middle class and the poor have been left behind. And the policies Mrs. Clinton is advancing, like paid sick leave for employees and an increase in the minimum wage, align with that emphasis.”

“But now, the former secretary of state must convince voters that she is the right messenger for the cause of inequality, not simply seizing on it out of political expedience.”

“Hillary Clinton made her most ringing endorsement yet of U.S. Senator Elizabeth Warren’s efforts to tamp down on ‘Wall Street’s irresponsible risk taking’ in a two-paragraph Time magazine article… Clinton is yet to reveal what economic policies she would bring to the White House if elected, but much of her rhetoric in recent days has had echoes of Warren, a hero of the Democrat’s progressive left wing,” Reuters reports.

Wrote Clinton: “She never hesitates to hold powerful people’s feet to the fire: bankers, lobbyists, senior government officials and, yes, even presidential aspirants.”