What happens to Trump if the Democrats crush the midterms October 31|Duration 4:57With the 2026 U.S. midterm elections threatening Republican control of Capitol Hill, CBC’s Ellen Mauro breaks down how a shifting balance of power could challenge President Donald Trump’s agenda — and the key tools he can use to counter Democratic opposition.

U.S. President Donald Trump's Justice Department has shown a willingness to intervene directly in Tuesday's midterm elections before polls have closed, breaking with decades of practice meant to avoid the appearance that its law enforcement powers are being used in a partisan manner.

In California, the Justice Department seeks to set aside mail-in ballots from about 20,000 voters it alleges are likely non-U.S. citizens ineligible to vote. The Trump administration asked the Supreme Court on Monday to temporarily block California from counting mail-in ballots from those voters.

It is one of two cases which underscore the department's willingness to intervene in election disputes before votes are counted. The cases have raised concerns among Democrats that, after polls close Tuesday, there will be an effort to sow doubt about the midterms, as Trump did with baseless claims of fraud following his 2020 election loss to Joe Biden, culminating in the Jan. 6, 2021 riot at the Capitol.

Voters enter the C. Blythe Andrews Jr. Public Library to cast their ballots on the final day of early voting for midterm elections in Tampa, Fla., on Sunday. (Octavio Jones/The Associated Press) Outside groups aligned with Trump filed more than 60 lawsuits challenging his 2020 defeat, all of which were unsuccessful.

"The right-wing fringe outside groups are not going to have to do that this year because the [Justice Department] is clearly standing ready and willing to do it," said Elisabeth Frost, a voting rights lawyer with Elias Law Group, which frequently represents Democrats in court. Analysis Economic frustration set to boil over in midterm elections Election denial has gone mainstream in the U.S. What does that mean for the midterms?

The House and Senate, which Republicans currently control by slim margins, could change hands if Democrats manage to pick up a net four seats in each chamber. All 435 House seats are up for election in the midterms, while only about one-third of the Senate's 100 seats are.

California, with 52 House of Representatives seats, can take weeks to count ballots and some of Tuesday's midterm races could be subjected to recounts and court challenges.

"Those within the recount or contest margin of error — the candidates, outside groups and the administration — will fight those tooth and nail," said Victoria Bassetti, senior adviser at States United Democracy Center, a non-profit group focused on protecting free, fair and secure elections.

Day 69:26How will Trump’s voter fraud claims affect the midterms? For months, U.S. President Donald Trump has made claims about rampant voting fraud and helped steer election deniers into positions of power over the midterm elections. Evidence suggests voter fraud is rare, but Jonathan Montpetit, a senior investigative journalist with the CBC, says there are signs Trump has been successful in sowing doubt about the vote. Data analysts question government's list The U.S. Constitution assigns the responsibility of administering elections to states, though the federal government has some oversight to protect against discriminatory and other illegal practices at the state and local level.

In the California case, U.S. District Judge David Carter slammed the administration's efforts in denying its request on Oct. 28.

"Never before in American history has the federal government, on the eve of an election, sought to coerce a state and local government to abandon their own constitutional elections procedures and bend to the will of the executive branch," he said.

What would a U.S. midterms win look like for Democrats and Republicans? | Hanomansing Live October 30|Duration 6:05The highly anticipated U.S. midterm elections are just days away with the Democrats seeking net gains of four seats in the Senate and three in the House to flip power in Congress from U.S. President Donald Trump's Republicans. Politics professor Chris Galdieri explains what a good night would look like for both parties.

The San Francisco-based 9th U.S. Circuit Court of Appeals also refused on Friday to block the ballots.

California has said that the state's safeguards against non-citizen voting are robust. As well, because the list originated from the Department of Homeland Security, state officials and immigrant rights groups fear it is being used as a pretext for contentious deportation efforts.

Multiple studies and state audits show that ineligible voting, including by non-citizens, is rare. When it occurs, it is disparate and not, to date, part of an organized effort that could sway a particular race.

An outside analysis of the list compiled by the Department of Justice has raised troubling questions. More than four in 10 names flagged as possible non-citizen voters in California by the Trump administration cannot be found on the state's voter rolls, said two data analysis members of UCLA's Voting Rights Project, who filed a lawsuit challenging it, along with the Los Angeles-based Coalition for Humane Immigrant Rights (CHIRLA). Canadians caught up in Trump voter fraud crackdown as U.S. accuses Canada of election interference

5 reasons why the Democrats might not take control of Congress in U.S. midterms The research found that 8,880 of the names, representing 42 per cent of the entire list, do not correspond to anyone in California's current voter file.

"The expert analysis further makes clear that the mandated voter list endangers a significant number of eligible California voters," said the filing, which was cosigned by Xavier Becerra, the Democratic candidate for California governor and an adviser to the UCLA Voting Rights Project.

The analysis also found that thousands of U.S. citizens appear to be flagged as ineligible to vote on the government's list. Alaska setback for Trump administration The administration has taken an increasingly aggressive approach toward how states run elections. The Justice Department has told election officials in all 50 states that they could face criminal prosecution if they knowingly allow non-citizens to remain on their rolls or cast ballots.

It has lost a series of lawsuits seeking to obtain voter rolls , including sensitive personal information, from dozens of states. Trump slams Democrats for Alaska's double Dan Sullivan drama October 29|Duration 2:01U.S. President Donald Trump is demanding an investigation after reports surfaced that Democratic staffers were told to 'find as many people named Dan Sullivan as you can" in an apparent effort to stack Alaska's midterm ballot with people sharing the name of incumbent Republican Sen. Daniel S. Sullivan. The Trump administration has also vowed to appeal a ruling in Alaska.

Alaska has become a particularly intense legal battleground after the New York Times reported that Democrat Mary Peltola's campaign was involved in recruiting retired teacher Daniel J. Sullivan to challenge Republican incumbent Dan Sullivan.

The Justice Department lawsuit, which Trump said he directed the department to file, asked a court to halt certification and order an investigation if the margin suggested voter confusion could have affected the outcome.

U.S. District Judge Sharon Gleason, in Anchorage, dismissed the case on Sunday, finding Alaska could not conduct such a probe while preserving the secrecy of ballots.

Analysis Dirty tricks or much ado about nothing? Why Alaska, for once, is front and centre in midterms Canada is in the U.S. midterm spotlight. Will the results be a blessing or a curse?

The lawsuit marks a rare federal intervention in the voting process and signalled a willingness by the administration to contest the election results in court.

Separate from the election result, the Justice Department has vowed to investigate whether any laws were broken in the effort that saw the politically inexperienced Dan Sullivan qualify for the ballot.

The administration already sought to restrict voting by mail for this year's midterms — a mode of casting ballots used more often by Democratic-leaning voters — but the Supreme Court in September rebuffed that effort .

According to an NBC News tracker, more than 24 million mail-in ballots have been cast so far, as of Monday.