With 2023 just days away, the Biden administration is facing a number of what former Defense Secretary Donald Rumsfeld called "known unknowns" in relation to its border and immigration policies.

The administration enters its third year in office plagued by an ongoing crisis at the southern border, which exploded shortly after President Biden entered office in 2021. FY 2021 saw more than 1.7 million migrant encounters, and FY 2023 exceeded that with 2.3 million.

So far, FY 2023 is on track to outpace both those years, with both October and November seeing larger migrant numbers than the corresponding months in previous fiscal years.

2022 IN REVIEW: HOW BIDEN'S BORDER WOES WENT FROM BAD TO WORSE 

But it isn’t just a case of numbers for the administration. There are multiple unknowns as to what will happen in 2023 that could determine what control officials have over the situation at the border, as well as how illegal immigrants are handled within the U.S.

Migrants Mexico Title 42

Migrants stand near the U.S.-Mexico border in Ciudad Juarez, Mexico, Monday, Dec. 19, 2022.  ((AP Photo/Christian Chavez))

Title 42

The Title 42 public health order, implemented in March 2020 during the Trump administration, has been the subject of litigation throughout 2022 and its future is still unclear — casting a significant shadow over the administration’s border efforts.

The Centers for Disease Control (CDC) announced in April that it was ending the order’s use to rapidly expel migrants at the border. However, a month later — with bipartisan fears about a new surge in migrants if the order was ended — a federal judge blocked the move in response to a Republican state lawsuit.

As a result, migrants continued to be expelled under the order, with the administration even expanding the order’s use to include Venezuelan nationals as part of an agreement with Mexico. 

However, in response to a lawsuit from the American Civil Liberties Union (ACLU) another federal judge found Title 42’s use unlawful, and ordered it be wound down on a Dec. 21 deadline.

But in yet another twist in the order’s history, Supreme Court Justice John Roberts placed a hold on that order earlier this month, keeping the order in place indefinitely as the court weighs in. On Tuesday, the Court in a 5-4 decision decided that Title 42 will remain in effect until the case can be heard on the merits, likely beginning in February or March 

The order’s end has raised fears from Democrats and Republicans of an even bigger surge, and the administration itself has projected between 9,000 and 14,000 migrant encounters a day when the order drops. But it says it has a six-point plan in place to deal with the surge.

How successful that plan will be, when it will go in place, and whether it will even be needed at all, is still not clear, and the fate of Title 42 could be the most significant determiner of border policy in 2023.

ICE guidelines

When the Biden administration took office, it went to work narrowing the scope of operations by Immigration and Customs Enforcement. It eventually issued rules for ICE officers which dramatically restricted them to three sets of illegal immigrants: recent border crossers, national security threats, and aggravated felons.

The new guidelines saw multiple legal challenges, while also coinciding with a dramatic drop in arrests and deportations of illegal immigrants. DHS Secretary Alejandro Mayorkas hailed the new guidelines, along with other rules, as having "fundamentally changed" interior immigration enforcement in early 2022.

But a federal judge, considering a lawsuit from Texas and Louisiana that argued that the guidelines were unlawful, blocked the guidelines from being enforced. The Biden administration took the matter to the Supreme Court.

The high court heard oral arguments on the case last month, but a decision is unlikely to be made until deep into 2023 — meaning that the cornerstone of the administration’s ICE policies is frozen until further notice. How that case is resolved will have a significant impact on what interior enforcement looks like across the U.S.

Republicans take the gavel

The political pressure on the administration over the ongoing crisis at the southern border has been intense over the last two years, but if anything it is likely to only intensify in 2023.

While the midterms didn’t meet the expectations of some Republicans, the GOP did pick up control of the House and will take the gavel in early January — giving the party a majority as well as control of the committees. And GOP leadership has indicated they intend to closely scrutinize the administration’s handling of the border crisis.

Within days of the majority being confirmed, GOP Leader Kevin McCarthy came out swinging — telling DHS Secretary Mayorkas that he must resign or potentially face impeachment.

"He cannot and must not remain in that position," McCarthy said. "If Secretary Mayorkas does not resign, House Republicans will investigate every order, every action and every failure to determine whether we can begin an impeachment inquiry."

REPUBLICANS, AHEAD OF HOUSE TAKEOVER, LOOK TO ZERO IN ON BIDEN ADMIN'S HANDLING OF BORDER CRISIS 

McCarthy said he had spoken to Reps. Jim Jordan and James Comer, the ranking Republicans of the Judiciary and Oversight Committees, respectively, and said they have his complete support to investigate the "collapse" of the border.

Jordan wrote to DHS officials telling them to prepare for in-person hearings and interviews, while also requesting more information about a Venezuelan parole program over concerns it may be using humanitarian parole illegally.

What those investigations and hearings uncover could be crucial in how the administration is able to conduct its policies. Not only could such moves increase political pressure on DHS and other agencies, it may also uncover details that could be used in lawsuits from Republican states in the courts.

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Separately, Republicans have rolled out a number of legislative blueprints to secure the border, focusing on border security and asylum reform. Should those measures pass the House, and then find even limited Democratic support in the Senate, they could end up on President Biden’s desk. If they receive his signature, that too could have a dramatic impact on how the border is handled.

But what measures those would be, how significant they are, and whether bipartisan agreement on border legislation is even possible, will be something that will be revealed in 2023.