Congress begins a new session today. Here are five things to watch for

As the world enters the new year, lawmakers gather at the US Capitol to begin the new Congress.

Friday marks the beginning of the work of the 119th Congress, with a Republican majority in both the US House of Representatives and the Senate.

This represents a triple Republican victory given that President-elect Donald Trump will also return to the White House later this month. The United States has not seen unified control over all three branches of government since 2017, when Trump was last in office.

Republicans are eager to start preparing an ambitious to-do list, but things may not come easy – and their majorities in both chambers of Congress leave little room for disagreement. The first test of the party's unity comes on Friday with the leadership elections in the House of Representatives.

Here are five things to watch as the new session of Congress begins:

Republicans may have a majority in the House of Representatives, but not by a large margin.

It will be tested once the session starts. The House of Representatives cannot certify election results or pass laws until lawmakers choose their next speaker, who is the leader of the House.

Despite Trump's endorsement, current House Speaker Mike Johnson faces opposition from many members within his caucus who remain unconvinced that he deserves a second chance.

The party's majority is so small that if Johnson loses just two Republicans in his campaign, it could trigger a cascade of ballots until Republicans rally around a lawmaker. In 2023, it took 15 rounds of voting and four days for Kevin McCarthy to win the speakership.

Johnson is already facing a strong “no” from Congressman Thomas Massie of Kentucky, but several other Republicans have put themselves in the “undecided” column.

The GOP remained with a five-seat majority when the final House races were called in the 2024 elections. But that shrank after Trump appointed several House members to serve in his administration.

“Do the math,” Johnson said during a press conference in early December. “We have nothing to save.”

In the Senate, lawmakers have already chosen a majority leader: South Dakota Sen. John Thune won an internal GOP vote.

That means senators can move into official business on Friday, but they will face challenges in other ways. Lawmakers are scheduled to begin a series of hearings to confirm some of Trump's controversial decisions Appointees to the Council of Ministers.

The Senate must sign off on about 1,200 appointments to the new president's administration, but some will come with tense hearings that attract public attention. They will first appear before a Senate committee and answer questions, before the full Senate votes.

Among the candidates is Trump's nominee for Secretary of Defense, Pete HegsethHe has been facing accusations of sexual assault since 2017, which he denies, in addition to his selection for the position of Secretary of Health and Human Services. Robert F. Kennedy Jris a vaccine skeptic with a history of spreading misinformation.

Trump's nominees were seen making their rounds on Capitol Hill last month to win over Republican senators. But the nominees will have to appear before bipartisan committees, meaning the hearings could get heated as senators from both parties use their platforms to address criticisms and grievances.

However, the Senate can choose to expedite Confirmation hearings for some national security nominees – in the wake of the New Year's terrorist attack in New Orleans that left 14 dead and a car exploded outside the Trump hotel in Las Vegas.

“The US Senate must confirm President Trump's national security team as soon as possible. Lives depend on it,” Wyoming Senator John Barrasso wrote in a post on X.

A nomination approved by the committee typically faces no opposition on the floor of the full Senate, but given some of the initial backlash to Trump's picks, the road to confirmation could be bumpy.

One item rising to the top of Congress's legislative to-do list is addressing the Trump Tax Cuts and Jobs Act of 2017, which expires in 2025.

The 2017 legislation – passed at a time when Republicans controlled the House and Senate – included a $1.5 trillion (£1.2 trillion) overhaul of the tax code, changing tax brackets and lowering tax rates for most taxpayers.

It was the biggest tax reform in decades. The largest cuts went to corporations and the wealthy, something Democrats called for to reverse.

Trump's campaign focused on the economy, pledging to extend tax cuts, cut corporate taxes further, and eliminate taxes on tips, overtime pay, and Social Security income.

How Congress will do that — extending the 2017 bill, a combination of old and new legislation or by other means — is up in the air.

Keeping the 2017 tax cuts in place would add an estimated $4 trillion to the deficit over the next decade, according to the Congressional Budget Office. This may not please many hard-line Republicans who strongly oppose increasing the country's debt.

We are expected to see legislation move on several key Republican priorities, from reducing illegal immigration to cutting government regulations.

There could be proposals to reduce military aid to Ukraine, impose new tariffs, cut spending on clean energy and strengthen border security.

In a November press conference, Johnson outlined a GOP agenda aimed at lowering inflation, securing the border, restoring the nation's energy dominance, implementing “freedom of education” and “draining the swamp.”

Lawmakers will also have to address the debt ceiling — the total amount the United States can borrow to meet its obligations. This issue actually came to light at the end of 2024 when lawmakers ran into a problem Government shutdown.

Trump called on lawmakers to raise or even suspend the debt limit in any spending deal, but that provision was dropped from the final version of the bill passed in both chambers.

It is possible that several priorities will be combined in what is known as a reconciliation bill, which allows Congress to pass a bill on taxes, spending and debt reduction with only a majority. This method avoids the possibility of filibuster in the Senate, where opposition lawmakers could delay or even obstruct the vote.

However they choose to handle the matter, lawmakers may spend more face-to-face time on Capitol Hill addressing their priorities next session.

Incoming Senate Majority Leader John Thune has scheduled more days and weeks for the Senate — including Mondays and Fridays, which are traditionally travel days.

The end of the last conference provided a glimpse of Influencing Trump and his allies On the congressional agenda.

Tech billionaire Elon Musk, who was tasked with advising the Trump administration on government spending cuts, posted dozens of times on his social media platform X to condemn the spending deal Johnson led with Democrats to avoid a government shutdown.

Trump and Vice President-elect J.D. Vance joined in, and the bill was crushed.

Both Trump and Musk threatened to withhold funding and support from incumbent Republicans who supported the bipartisan spending bill, raising questions about the extent of their influence on the legislative agenda.

Musk and pharmaceutical entrepreneur Vivek Ramaswamy may have more opportunities to get involved. The couple will co-lead a newly formed advisory committee focused on regulation and spending cuts.

On the other side of the party, Democrats are regrouping, hoping to reclaim the House during the 2026 midterm elections. We are expected to see center-left lawmakers vying for influence.

Groups within the party all hope to shape its future — such as the Problem Solvers Caucus, a group of lawmakers focused on strengthening bipartisan legislation; the Blue Dog Coalition, a group of centrist Democrats; and the centre-left, the “pragmatic” New Democratic Coalition.