WASHINGTON — After eight years in the minority, Democrats are set to regain control of the House in January, bringing divided government — and ambitious oversight — back to a deeply polarized Washington.

Unlike the last time they held the levers of power in the lower chamber, they won't have a Democratic Senate or president to help turn their legislative dreams into reality. What they will have: very real subpoena power — and a long list of potential executive branch targets.

When they assume the majority early next year, Democrats are planning to make up for lost time on both fronts — though some of the most ambitious items on their agenda are likely to run into a few reality-based roadblocks.

They'll be introducing a wave of policy proposals demonstrating the party's priorities on a range of issues, despite the vanishingly small odds that the GOP-controlled Senate would take up any of the bills — and even smaller odds that President Donald Trump would sign them into law.

More concretely, they'll be flexing their new investigative muscles with a focus on ethical questions swirling around the president, his finances, and multiple members of his Cabinet — even though they're likely to face legal battles and other pushback that may significantly slow or even stop the progress of some of their highest-priority likely probes.

Even so, Rep. Adam Schiff, D-Calif., who is expected to become the chairman of the House Intelligence Committee, has said that he wants to make sure no stone was left unturned in the GOP’s investigation into potential collusion between the Trump campaign and Russia during the 2016 election.

Other committees — including Oversight and Government Reform, Judiciary and Ways and Means — are also expected to pursue investigations into the administration.

The expected chairman of Judiciary, Rep. Jerrold Nadler, D-N.Y., told MSNBC's Ari Melber Tuesday night that "all options are on the table" if Trump tries to "sabotage" the Russia probe or fires "key people" or abuses the pardon power.

"We’ll use subpoena power if we have to, when we have to," he said.

And Rep. Elijah Cummings, D-Md., expected to become chairman of the Oversight panel, plans to look into the administration’s immigration and child separation policies, financial conflicts of interest, possible violations of the Constitution’s emoluments clause, and voter suppression efforts, to name just a few entries on a long list of potential targets.

The first step in that process: staffing up a new investigative army. In 2011, for example, the number of Republican staff members on the Oversight Committee quickly shot from 40 to 80.

“Our staff doubled overnight,” said Kurt Bardella, who served as deputy communications director and senior adviser to Rep. Darrell Issa, R-Calif., when he led the Oversight Committee in 2011. “You really can’t underestimate the amount of manpower you really get when you’re in the majority for this particular committee, which enables you to conduct five, six, seven, eight investigations simultaneously.”

Ways and Means is one of several committees that could seek to obtain President Trump’s tax returns, which he has refused to release since his presidential campaign, saying he is under audit by the IRS. According to a Democratic aide the committee — along with the Senate Finance Committee and the Joint Committee on Taxation — has the ability to request a person’s tax returns under the tax code.

The chairman could submit a written request to the IRS to provide the information. If the Treasury Department were to deny it, House Democrats would have to decide whether to pursue the tax returns through a legal route. If they are obtained, the chairman would have to designate the panel’s members as “agents” to read the returns. They would then have to vote to make the documents public and report them to the full House.

It would be far from an easy win: The process, once launched, could drag on for months, or even longer. Publicly, Trump has downplayed any concern over the prospect. "I don't care. They can do whatever they want, and I can do whatever I want," he said Monday of the idea of a drawn-out battle for his tax returns.

However that fight plays out, Democratic leadership has pledged its full support for the general idea of aggressive investigations. Impeachment is another story.

In the run-up to the election, many Democrats avoided discussing the possibility — which, if it were acted on in the House, would likely be politically dead on arrival in the Senate. House Minority Leader Nancy Pelosi, D-Calif., publicly dismissed it as “not a priority” for her party.

While Pelosi, 78, will have to formally be re-elected as speaker of the House, she has repeatedly expressed confidence that she will retake the gavel despite some dissatisfied members who want a new leader.

Rumblings over the last year of a potential challenge to Pelosi for speaker again if Democrats won the House were driven in large part by a relatively small group of Democrats running in predominantly GOP districts. (Asked Tuesday night if she had a message for any candidates in that group who had won election, Pelosi said only: "Congratulations on winning.")

House Democrats have planned to hold leadership elections for their caucus the week after Thanksgiving, which will be when House Democrats will vote to decide whether to re-elect Pelosi as their leader, paving the way for her to likely win the speakership in January when they hold the formal vote on the floor. And unless there are challenges from other members, the current ranking members on committees will likely become the chairs.

The dynamic on Capitol Hill between the two parties will in many ways mirror that after the Republican takeover of the House in 2011, which guarantees one thing: even more gridlock. At the time, Democrats controlled both the White House and Senate and there was only so much lawmakers were able to achieve as the GOP took a series of effectively symbolic votes to dismantle Obamacare and cripple more of President Barack Obama’s policy initiatives.

Back then, the new GOP majority came with a new set of headaches: a rebellious group of conservatives who didn’t always stand behind GOP leadership. Democrats are wary of encountering their own internal divisions — between the more establishment-oriented and more progressive wings of the party — as they prepare to shape their message ahead of the 2020 presidential election.

“It’s easier to be united in the minority than it is to be in the majority,” said Nadeam Elshami, who served as chief of staff and senior communications adviser to Pelosi when she served as speaker of the House from 2007 to 2011.

House Democrats waded through internal divisions in 2007 as they debated whether to fund the war in Iraq and the caucus was “absolutely split,” Elshami recalled, which led to a rift with President George W. Bush early on after the Democratic-controlled congress passed an emergency spending bill saying that the U.S. had to leave Iraq by a certain date.

“The president vetoed that bill,” he said. “Really, off the bat, it wasn’t a very good relationship.”

Former Rep. Barney Frank, D-Mass., who chaired the House Financial Services Committee at the time, remembers that while he experienced bipartisanship in the beginning, it didn’t last long. One of the first major bills he shepherded through his committee was a measure to outlaw bad subprime mortgages and the committee’s senior Republican, Rep. Spencer Bachus, R-Ala., voted for the bill along with several other GOP members.

“The reaction of the other Republicans on the committee was fury, and after [Bachus] cooperated with us in passing the bill, he was threatened with the loss of his position as ranking member — and from then on, I got no cooperation from any of the Republicans,” Frank said.

A similar dynamic is sure to return next year, with some newly-minted members of the Democratic majority unlikely to be in a mood to hand the president any easy political wins — even in areas where their priorities might appear to have some overlap.

Democrats, for instance, are expected to reintroduce their Better Deal legislative plan that includes proposals to lower the cost of prescription drugs and to rebuild the nation’s infrastructure, both of which have been policy goals touted by Trump. They'll also be looking to enhance election security and reduce the role of money in politics, which Pelosi recently said would be their first piece of legislation.

While they’ll put these proposals forward, there will be only so much they’ll be able to accomplish with President Trump in the White House and a GOP-controlled Senate — an approach more likely to lend itself to symbolic votes than actual law.

Technically, leaders from both parties have expressed a willingness to reach bipartisan deals. In reality, the energy to reach them will be limited, especially when Democrats begin to flex their new investigative muscle.

Then there's the baggage of Trump's own history in talks on the Hill, which has been littered with false starts and failed negotiations — meaning the most concrete action out of the new Congress is likely to come in probes of the Trump White House, not compromise with it.

Infrastructure, which fell by the wayside in the first two years of Trump’s presidency, has been mentioned as one area with the potential, however remote, for cooperation. House Democrats will likely reintroduce the infrastructure plan that they outlined earlier this year, calling for an investment of $1 trillion to rebuild the nation’s roads, bridges, transit, rail, schools and water systems. Rep. Peter DeFazio, D-Ore., ranking member on the Transportation and Infrastructure Committee, has already gotten a head start by recently meeting with White House legislative director Shahira Knight to discuss ideas.

But Republicans — who retain control of the lower chamber for the next several weeks — still have a shot at boosting their own agenda, with one last chance next month to provide significant funding for the president’s wall along the U.S.-Mexico border during his first term. Of course, Senate Democrats, who have blocked border wall funding so far this term, are likely to do the same late this year.

And so the Democratic goal of derailing Trump policies such as hard-line immigration proposals and efforts to further roll back environmental regulations will take center stage. Come January, the new House reality is that concrete policy action is less likely to involve advancing Democratic goals than it is blocking the president's priorities.