OPINION — 2018 will go in the books as a bad one for most Republicans. They picked up two seats in the Senate, but lost 40 in the House. Their numbers among women in the House shrank from 23 to 13, and President Donald Trump can’t give away his chief of staff job.

Ask anyone who’s been there: The only thing worse than losing the majority in Congress is every day after that, when chairing committees and holding press conferences is replaced by packing boxes and saying goodbye to staff.

It’s gotten so bad for some of the 40 House members who lost in November that they’ve stopped showing up for votes at all. But the real drudgery belongs to the Republicans who won. If 2018 seems bad, here are five ways that 2019 is going to be even worse:

1. Democratic oversight. There’s a new sheriff in town, or more specifically, there will be many new sheriffs in town once Democrats take over all the standing committees of the House in January, not to mention any select or special committees they’ll have the power to create in the future.

Already, press coverage of incoming Democratic chairs Rep. Elijah Cummings at Oversight and Government Reform, Jerry Nadler at Judiciary, and Adam Schiff at Intelligence reads like a primer on the horsemen of the apocalypse, and with good reason. After two years of House committees mostly cheerleading for the Trump administration instead of overseeing it, Democrats are poised to issue subpoenas on everything from the president’s possible violation of the Emoluments Clause in the Constitution to Russian interference in the 2016 presidential elections to the administration’s child separation policy at the southern border.

Investigations will also fire up into possible abuses by recently or not-so-recently departed Trump cabinet secretaries. (Think outgoing Interior Secretary Ryan Zinke and his robust travel schedule or former HHS Secretary Tom Price’s eyebrow-raising stock trades or Ivanka Trump and Jared Kushner’s staffing costs.)

If Hillary Clinton was good enough for Republicans to go after as recently as a week ago, very little will be too old or off-limits for Democrats and their focus on the Trump administration.

2. A Democratic house agenda. After two years of controlling both Houses of Congress and the White House, Republicans will have to adjust to reacting to Democratic priorities in the House instead of ignoring them.

Look for likely Speaker Nancy Pelosi to move quickly and strategically on health care costs, infrastructure spending, government ethics and gun safety. Not only are they all issues on which midterm voters overwhelmingly supported Democrats, they are also areas where Trump is on the record saying he wants to make progress, but Senate Republicans have done the opposite.

That dynamic could leave Republicans feuding, the public frustrated, and Democrats with a powerful argument for voters to send more members of their party to Washington in 2020 to get the job done.

3. A shrinking electorate. From Rep. Elise Stefanik to Rep. Ann Wagner and outgoing Rep. Mia Love, there’s no shortage of women calling on the GOP to change not only what they’re doing, especially when it comes to attracting female and minority voters, but also how they’re doing it. So far, GOP leaders don’t seem to be listening.

If their own members can’t convince them to adjust course, the numbers should — including the fact that House Democrats rolled to midterm victories thanks to support from 59 percent of women, 90 percent of African-Americans, 69 percent of Latinos, 77 percent of Asians and 59 percent of Americans with a college degree.

Stefanik, who headed up a successful recruiting effort in 2018 only to see many of those candidates struggle on Election Day, has said GOP leaders need to help elect more women in primaries. Love wants Republicans to meet minority voters where they live, not just ask for their votes when it’s time to campaign. It’s excellent advice from young women who know from experience that the GOP’s universe of voters will continue to contract if the party doesn’t change course quickly.

4. The Mueller investigation. Special counsel Robert Mueller has already indicted more than 30 people as part of his investigation of Russian interference into the 2016 presidential election, including more and more associates with close ties to the president who are working with prosecutors and seemingly talking — a lot.

The investigation will almost certainly come to a close in 2019, with the results ranging from the president having his name cleared to a possible impeachment effort and a resulting constitutional crisis. As much as the White House and Senate Republicans will want to dictate their own agendas in 2019, the Mueller probe has the potential to upend it all.

5. Recruiting challenges. The GOP can’t retake or retain power in Washington without recruiting top-notch candidates to run in 2020, but it’s hard to sell tickets on the Titanic.

The good news for Republicans is that the pendulum in politics always swings back. They will eventually be back in control of the House again someday. The bad news is there’s no telling how long their wilderness years will last or how cold they will get between now and then.