President Obama and Vice President Biden walk back to the Oval Office of the White House in Washington the day after the election. (Pablo Martinez Monsivais/AP)

The biggest stain on Barack Obama’s political legacy may turn out to be the decimation of the Democratic Party on his watch.

The 2016 election has brought a moment of reckoning — and a new era to the party.

Democrats have been shut out of power in Washington, with the White House and both chambers of Congress in GOP control starting in January. In state houses across the country, their ranks have been decimated.

And for the first time in a quarter-century, there will be no one named Clinton in the Oval Office or on deck. Obama and Vice President Biden are also moving offstage.

That is certain to set off a struggle for the soul and direction of the party — and give an opening for other leaders to fill the void in a party with a thin bench.

As a candidate, Donald Trump vowed to dismantle some of President Obama's key achievements. Washington Post White House reporter David Nakamura breaks down what the Obama administration is worried about going forward. (Sarah Parnass/The Washington Post)

Incoming Senate minority leader Charles E. Schumer (D-N.Y.) is a talented legislator and skillful politician who is always eager to take the spotlight. But he is not likely to be the party’s entire answer.

“I think there’s going to be a fight in the Democratic Party about which direction to go in,” political consultant Joe Trippi said. “That’s healthy for the party long-term, but it’s going to be painful over the next few years. There won’t be a Democratic president to hold the factions together.”

In particular, Trump’s victory over former secretary of state Hillary Clinton is certain to embolden the party’s liberal wing.

Sen. Bernie Sanders (Vt.), who challenged Clinton for the Democratic nomination, has argued, with questionable plausibility, that he would have been a stronger standard-bearer against Trump. He was a harsher critic of Wall Street and a more full-throated foe of free-trade deals.

The left says that the Democrats’ salvation is to reclaim their New Deal roots and move the party onto a more populist footing, as championed by Sen. Elizabeth Warren (D-Mass.).

The lesson of their defeat by Donald Trump is that “Democrats need to speak more directly to voter anger,” said Adam Green, co-founder of the Progressive Change Campaign Committee. “They’ll hopefully remold the party in Elizabeth Warren’s image and have a more authentic message that channels that anger in a more productive direction than Donald Trump’s authoritarian message.”

These former Obama strongholds sealed the election for Trump

An electoral shutout has added new urgency to an argument that has been going on within the party, in one form or other, since the 1980s.

The danger of all this is that the Democrats could move too far left and give Republicans space in the center.

“The question is, can left-wing populism really beat right-wing populism? There’s no argument for that,” said Matt Bennett, a senior vice president of the centrist organization Third Way.

Trump is unorthodox in his views — his victory speech focused on rebuilding America, rebuilding roads and bridges and airports and hospitals.

Republicans probably benefited from not having to run a hard-right candidate as their nominee. That, however, means it is far more difficult for the opposition party to figure out precisely what it is to oppose.

What is undeniable, however, is that there has been a systematic erosion of Democratic power during Obama’s eight years in office, and particularly from the heady days of his early presidency.

“I think of this job as being a relay runner,” Obama said Wednesday morning, as he pondered the results of the election. “You take the baton, you run your best race. And hopefully, by the time you hand it off, you’re a little further ahead, you’ve made a little progress.”

In purely partisan terms, however, the opposite has happened.

Trump’s candidacy appealed to voters, including traditional blue-collar Democrats, who believe they have been left behind in the belated economic recovery from the financial meltdown that was occurring as Obama was elected in 2008.

“His administration delivered to Wall Street, and did not to Main Street,” said former congressman Dennis Kucinich (D-Ohio), an ardent liberal. “The Democrats were basically obtuse to this, because it was all about winning and holding power, and it was not about deliverables to the American people.”

In Obama’s first year in office, buoyed by the biggest presidential election victory since 1988, the Democrats expanded their House majority to 257-178; in the Senate, they could count a filibuster-proof majority for the first time since the Jimmy Carter era.

As a result, their numbers were robust enough to muscle through virtually all of Obama’s early agenda, most notably his health-care overhaul.

They lost control, however, in the devastating midterm election of 2010, which was fueled in large part by a backlash against the health-care law and government bailouts of Wall Street and industry. Democrats’ numbers further eroded in 2014.

Democrats’ hopes of regaining the Senate were dashed on Tuesday, when Trump’s victory provided a badly needed updraft for a handful of endangered GOP incumbents.

The lesson: Without Obama himself on the ballot, his army of young and minority voters would not show up in numbers needed to keep his party afloat.

Unlike Franklin Roosevelt’s durable New Deal coalition, the impressive political operation that Obama built does not appear transferrable to other Democrats — and therefore, may not live on past his presidency.

White House press secretary Josh Earnest said Wednesday that the math is undeniable, if perplexing. “There are a lot of people . . . who voted for Barack Obama in 2008, who voted for his reelection in 2012, and voted for Donald Trump in 2016,” Earnest said. “I don’t have an explanation for that, to put it bluntly.”

Meanwhile, the party has also been hollowed out in state capitals across the country. Where Democrats held 29 governorships when Obama was inaugurated, they can count only 15 in the wake of Tuesday’s election. In 2017, Republicans could tie the record for controlling governorships, which is 34, set in 1922 when Warren Harding was president. (One governor is an independent, and a recount is possible in North Carolina, where the Democrat has a narrow lead.)

During the Obama presidency, more than 900 Democratic state legislators were defeated.

On Tuesday, Republicans picked up additional legislative chambers, and continued to make gains in state houses, with 24 states now having the “trifecta” control of both houses of the state legislature and the governor’s mansion. The victories for the GOP Tuesday included picking up the Kentucky House for the first time in almost a century and gaining control of the Iowa Senate.

Republican gains at the state level have unnerved Democrats and led to the launch this year of an effort designed to restore Democratic state-level power in advance of the 2020 Census and the redistricting that follows.

The new initiative, called the National Democratic Redistricting Committee, will be led by former attorney general Eric H. Holder Jr. It was launched in August with strong backing from the White House.

Dan Balz and Alice Crites contributed to this report.