This November, voters will determine which party controls Congress for the last half of President Biden's first term. Democrats control both the House of Representatives and Senate now. What was once widely expected to be a wipeout for their party has turned into a competitive battle. It's possible that Republicans pick up one or both chambers of Congress - or neither.

What happens in these elections will drastically reshape the next two years before Biden potentially runs for reelection - and potentially runs against Donald Trump again. With Congress under Democratic control, he could have another chance to pass major liberal priorities. Under split or all Republican control, his administration could spend the next two years defending itself from investigations - and maybe even impeachment.

Here are the three likeliest scenarios for who will win Congress, and what they've talked about doing with that power.

1. Republicans take the House, Democrats keep the Senate

One potential outcome is that Congress is split between the two parties, with Republicans taking over the House but Democrats holding onto their Senate majority. With partisanship so intense these days, it seems unlikely that any major legislation gets passed. But there are plenty of investigations and political maneuvering to keep both parties busy.

In a GOP house, Republicans could ...

Disband the Jan. 6 committee: House Republican leaders have expressed zero interest in investigating the Jan. 6 attack on the Capitol. House Minority Leader Kevin McCarthy, R-Calif., has ignored a subpoena from the committee to testify about his conversations with Trump that day. Instead, McCarthy has threatened to investigate telecom companies that hand over phone records to the committee, should Republicans gain power. Other House Republicans have considered how to launch investigations against the Jan. 6 committee members themselves.

Investigate Hunter Biden: There are several potential storylines related to President Biden's son that animate the right. He apparently left a laptop in a Delaware shop before the 2020 election that made its way into the hands of Donald Trump's allies. (The contents that The Washington Post could authenticate suggest he profited because of his name and connections - like through dealings with a Chinese energy company - but that his father did not.) Also, there was a federal investigation looking at whether he committed tax fraud and lied to pass a background check to buy a gun; that seems to have fizzled. But Republicans have promised to pick things back up with Congress's investigatory powers if they get the majority. Rep. Jim Jordan (R-Ohio), a staunch Trump defender, could be in a leadership position to launch many of these investigations.

And start lots of other investigations: Republican leaders will likely be under enormous pressure - including from Trump himself - to use their newfound investigatory powers in the House to dig into pretty much everything about the Biden administration. That includes how he ended the Afghanistan war (which some Democrats also wanted to investigate), as well as much more politically charged matters, like the FBI search of Mar-a-Lago, Biden's border policy and maybe even investigations that lend credence to Trump's false election fraud claims, reports The Washington Post's Jacqueline Alemany.

Maybe impeach Biden (or others): There are far-right Republican representatives who would vote to impeach Biden on day one of having control of the House. "I have consistently said President Biden should be impeached for intentionally opening our border and making Americans less safe," Rep. Bob Good (R-Va.) said. House leaders of both parties historically hesitate before pursuing such a drastic, time-consuming attack - one that could backfire on their party. But you can imagine a groundswell of support in the Republican conference for writing up impeachment articles against Biden or various members of his Cabinet. (The transgressions that qualify for impeachment that the Constitution lays out - "high crimes and misdemeanors" - are in the eye of the beholder.)

Meanwhile, in a Democratic-controlled Senate, lawmakers would likely ...

Confirm judges: If Republicans only take the House, that means Democrats will still control the Senate (albeit narrowly). There's not much they could do to stop GOP House investigations into Biden. But they probably would help the president out by continuing to approve his nominations for judges. In fact, it might be the only thing they could do in a split Congress. That job is only the Senate's purview, and Biden's choices can't be filibustered by Republicans. Like Trump before him, Biden and Senate Democrats have raced to try to fill empty spots on federal courts across the nation, aware of how much impact these judges have on investigations (like into Trump) and disputes over policy (like forcing Biden to continue a controversial Trump-era deportation policy called Title 42).

2. Republicans win both chambers

The party out of power almost always picks up seats in Congress in midterm elections. And Republicans need to pick up a total of just five (out of 435) in the House to grab the majority, and just one out of 35 in the Senate. Their momentum has been blunted by the overturning of Roe v. Wade, but it's still possible for the party to take both chambers of Congress.

Stymie Biden's agenda: In the first two years of Biden's presidency, Republicans worked with him on a surprising number of bipartisan issues: infrastructure, veteran health benefits, competitiveness with China and gun safety. But with two years to go before a presidential election, Republicans have more incentive to block Biden's agenda. That means Biden can expect Republicans blocking any of his spending requests for pandemic aid, climate change and anything else that comes up. There could even be shutdown threats as both sides try to gain leverage in spending bills.

Hold up court vacancies: We're not expecting vacancies on the Supreme Court in the near future, but anything can happen. And if a seat opens up, the top Senate Republican, Mitch McConnell, has demonstrated a ruthless ability to hold it open until a Republican president could appoint someone. More likely: A Republican Senate would slow down or even block many of Biden's picks to be federal judges.

A national abortion ban: Sen. Lindsey O. Graham, R-S.C., got the ball rolling when he introduced legislation to ban abortion across the nation after 15 weeks. Senate Republican leaders immediately distanced themselves from the idea. But if their party has both chambers of Congress for the first time since the fall of Roe, there will likely be a strong push from their right flank to at least bring a ban up for a vote. (Democrats in the Senate would filibuster it.)

Debate sunsetting the safety net: By sunset, we mean force Congress to reauthorize Social Security and Medicare every five years, rather than let the programs continue automatically. It's a controversial proposal by Sen. Rick Scott, R-Fla., who is in charge of getting Senate Republicans elected this year. McConnell slammed that idea and probably would not ever bring it up for a vote. But at least one prominent Republican senator - Ron Johnson of Wisconsin - has endorsed a version of this. That could mean Republicans at least have a debate (if not a vote) on ways to curb entitlement programs. Scott has also proposed raising taxes.

3. Democrats keep both chambers

This scenario is the least likely of the three. The party in power almost always loses seats in Congress in midterms, and Democrats can only afford to lose a few House seats and just one Senate seat. In addition, redistricting and Democrats being concentrated in cities puts the party at a structural disadvantage to keep the House, in particular. But if they had their dream election and ended up in this scenario, what Democrats could accomplish would depend on the strength of their Senate majority.

Take another whack at liberal priorities: Democrats would have a second shot at trying to pass national protections for abortion, same-sex marriage and voting rights. They could also try to pick up the pieces of Biden's Build Back Better agenda, passing more climate policy and expanding the government safety net.

If they have a really great election and actually expand their majority in the Senate by two seats (it's difficult but possible), they would have enough votes to break through filibuster to do some of this, because they wouldn't need the votes of Sens. Joe Manchin III, D-W.Va., and Kyrsten Sinema, D-Ariz., to end the filibuster. But if their majority stays at 50-50 or even 51-49, it's deja vu all over again for Democrats and Biden.

Limit what a President Trump could do: Democrats are starting to think about what happens if Donald Trump - or another like-minded candidate - wins the presidency. They've already proposed legislation to make it harder for a president to filter out federal government workers who don't agree with them, or to protect whistleblowers in the federal government.

Maybe try to keep Trump from running: The New York Times reports that some Democrats are drafting legislation to prevent Trump from running for president due to his active role in the Jan. 6 attack. But liberal activists have already tried and failed to argue in court that the Constitution prevents members of Congress who were involved in Trump's Jan. 6 rally from holding public office.