Barack Obama offered a welcoming hand to President-elect Donald Trump on Thursday during a 90-minute meeting at the White House, and for his part, the mogul who stunned the world was equally conciliatory, speaking of his respect for the president and promising to seek his counsel in the future.

After years of Trump spewing invective about the president and after months of Obama all but laughing out loud at his tormentor’s candidacy, it was a rare moment of civility and national unity.

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But not every Democrat was willing to give Trump a pass and wish him well.

Thursday marked the beginning of the struggle for control of a dejected and leaderless Democratic Party, and firebrand Senator Elizabeth Warren of Massachusetts seems to be making a bid for progressives, led by her, to take charge.

Early as it is, she may also be positioning herself as the Democratic champion of working-class America best equipped to challenge Trump in 2020.

In a speech Thursday before a meeting of the AFL-CIO in Washington, Warren told union leaders: “We will stand up to bigotry. No compromises ever on this one. We will fight back against attacks on Latinos, on African Americans, on women's, on Muslims, on immigrants, on disabled Americans, on anyone.

“Whether Donald Trump sits in a glass tower or sits in the White House, we will not give an inch on this, not now, not ever."

Later in the day, during an interview with Rachel Maddow on MSNBC, Warren said, “Look, this is painful. This really and truly hurts … But we are going to fight back. We are not turning this country over to what Donald Trump has sold.”

All that being said, Warren pointed out that Trump has said he wants to reenact the Glass-Steagall Act that placed limits on big banks, raise the minimum wage and protect Social Security. “We’ve got some places there where we can overlap,” she said. Warren also said that if Trump can advance health care measures, “that will be helpful” and that she would work with him.

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But she said that if he intends to “unleash Wall Street to ruin the economy again, no.” All that does not sound like some random senator. That sounds like the presumptive leader of the party.

And there is no doubt that the Dems need another hero.

Had Hillary Clinton done the expected and won the presidency, the centrist Clinton Machine would again be in control of the Democratic Party. But with the Clintons now relegated to the political wilderness – or at least the countryside of suburban New York, where they were seen walking in a park yesterday – the party is up for grabs.

Obama could take the reins if he wanted to do so, but after eight grueling years, his more appropriate role is an elder statesman. With an awakened working-class electorate more likely to find common ground with the progressives than the centrists, the door is open for Warren to move into the vacuum.

However, Warren is not the only progressive with the stature to emerge as the voice of the party.

Senator Bernie Sanders of Vermont, whose insurgent run at the Democratic nomination inspired an unlikely nationwide movement, certainly could lay claim to the title of party leader. Many of the economic positions he championed – and shared with Trump, such as opposition to what they both called job-crushing trade deals -- might have found resonance with the so-called forgotten Americans in the Rust Belt who powered a Republican victory. And there are plenty of liberals who think he could have won.

In an interview with the AP yesterday, Sanders called the fact that working-class voters rallied to Trump “an embarrassment” and did not rule out another run in 2020.

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"You cannot be a party which, on the one hand, that says we’re in favor of working people, we're in favor of the needs of young people, but we don't quite have the courage to take on Wall Street and the billionaire class,” he said. “People do not believe that. You've got to decide which side you're on."

Sanders would be 79-years-old if he took office in 2021, however, making him almost a decade older than the oldest person ever elevated to the White House, President-elect Trump.

Warren, on the other hand, would be a mere 71.

Four years, however, is plenty of time for a younger progressive to emerge. But first, the left wing of the Democratic Party has to seize the day.